The Grim Adventures of Billy & Mandy season 1

The Grim Adventures of Billy & Mandy
Season 1
DVD cover
No. of episodes	18 (50 segments)
Release
Original network	Cartoon Network
Original release	August 24, 2001 (2001-08-24) – October 22, 2004 (2004-10-22)
Season chronology

The first season of the American animated television series The Grim Adventures of Billy & Mandy originally aired on Cartoon Network in the United States from August 24, 2001, to October 22, 2004. It consisted of 18 episodes, including the 49 Grim & Evil episodes, one exclusive episode, and the half-hour Halloween special (also made originally for Grim & Evil), in which Billy, Mandy, and Grim face against Jack O'Lantern.

This season introduces the three title characters, boy-wizard Nigel Planter and supporting characters such as Dean Toadblatt, which constitutes a parody of the Harry Potter franchise. Other characters that make major appearances include Mandy's nemesis, the popular and snobby Mindy; Nergal Junior, the son of Nergal, and Billy's aunt Sis; and Jeff the Spider, who is hatched from an egg by Billy.

Other characters that were also introduced are Hoss Delgado, who battles zombie brownies alongside Billy; and Eris, who keeps scheming to create chaos with the Apple of Discord.

Episodes

No.	Title	Directed by	Story by	Storyboarded by	Original air date (U.S.)	U.K. air date
1a	"Meet the Reaper"	Maxwell Atoms	Maxwell Atoms	TBA	June 9, 2000 (2000-06-09) (pilot) August 24, 2001 (2001-08-24)	TBA
When Billy's pet hamster, Mr. Snuggles, celebrates his 10th birthday, the Grim Reaper comes for him. Billy's friend Mandy is reluctant in allowing it, so she proposes a deal to the Grim Reaper: if he beats the kids in a game, he can take the hamster, but if he loses, he will spare the hamster's life and become their "best friend forever". The Grim Reaper transports the kids to limbo, where he challenges them to a game of limbo. Despite his best effort, Grim ends up losing because he is attacked by Mr. Snuggles at Mandy's own command. Note: Originally aired as part of Cartoon Network's "Cartoon Cartoon Weekend Big Pick", this episode was released on CartoonNetwork.com on June 9, 2000, and later aired on the channel proper on August 25, 2000, later being named the pilot winner to be picked up by the network for its own series. This is also the only episode not produced by Cartoon Network Studios, having been produced in 1999 by Warner Bros. Animation's subsidiary Hanna-Barbera, and the only episode of the series to be animated with cels, as the series began using digital ink and paint animation when it became a full series.
1b	"Skeletons in the Water Closet"	Dave Brain	Greg Miller	Greg Miller	August 24, 2001 (2001-08-24)	TBA
Billy's mother, Gladys, first notices Grim in Billy's bed, then in the shower and subsequently starts to get panic surges thinking that Billy is in danger. Meanwhile, Harold, Billy's dad, just thinks that Gladys is imagining things. In the end, Gladys ends up moving in with Aunt Sis to try and calm herself down.
1c	"Opposite Day"	Dave Brain	Maxwell Atoms	Mike Stern	August 31, 2001 (2001-08-31)	TBA
Billy and Mandy tell Grim it is "Opposite Day" and that, when they say something, they really mean the opposite. Due to his difficulty understanding the concept of Opposite Day, Grim has to do Mandy's chores. Finally, Grim thinks he understands when Billy and Mandy say they "want" pie, meaning they "do not want" pie. However, Mandy then says that when she said it was Opposite Day, it really was not.
2a	"Get Out of My Head!"	Dave Brain	Maxwell Atoms	Maxwell Atoms	September 7, 2001 (2001-09-07)	TBA
After watching a movie, Grim teaches Billy to possess people by jumping into their heads. Billy possesses Mandy and makes her do assorted things like flirting with Irwin, kissing Mandy's mother, going into both men's and women's restrooms and eating earthworms. In the end, Billy leaves Mandy's head, but later that night, Mandy possesses Billy's cat, Milkshakes, to maul him as a form of revenge.
2b	"Look Alive!"	Brian Hogan	Maxwell Atoms	Paul McEvoy	August 31, 2001 (2001-08-31)	TBA
Grim is bored of being left alone while Billy and Mandy are not with him. Grim decides to fulfill his dream by working as a swimsuit model, but, as he is a corpse, he is not hired. Subsequently, Billy and Mandy give him a makeover to look more human. In the end, Grim gets the job in a TV ad, but he is only in the commercial for a few seconds and is portrayed as an ugly person.
2c	"Mortal Dilemma"	Brian Hogan	Amy Rogers	Michael Diederich	September 7, 2001 (2001-09-07)	TBA
Grim misses his life as the reaper of souls and, due to his bet, he cannot return to the Underworld, much to the hilarity of his Underworld co-workers. Having a sudden epiphany, Grim decides to be good and help people rather than try to take their souls. However, Grim's attempts at being good are faced with resistance from people, who are scared off by his appearance.
3a	"Fiend is Like Friend Without the 'R'"	Brian Hogan	Craig Lewis	Paul McEvoy	December 14, 2001 (2001-12-14)	TBA
Billy wanders into a junkyard, where a massive hole in the earth opens up and pulls him down in. Later, Mandy and Grim get pulled in as well. They land at the center of the Earth, which is home of Nergal, a devilish creature. The lonely Nergal, who has been watching Billy and Mandy for some time, wants Grim to hand over the kids to him so they can be his friends forever. Grim happily leaves the kids behind as he returns to the surface; however, he later goes back for them because he can't handle the guilt of abandoning his friends. In the end, Grim is defeated by Nergal's electrified tentacles, but Mandy defeats Nergal merely by kicking him in the shin.
3b	"Recipe for Disaster"	Dave Brain	Maxwell Atoms	Mike Diederich	October 5, 2001 (2001-10-05)	TBA
Billy, Mandy, Grim, and Pud'n are part of the "Person Scouts" (a Boy Scouts-esque organization) and need to sell cookies in order to win a badge. However, as Billy eats all of the cookies, Grim proposes to bake their own cookies using his aunt Kali's secret recipe. The cookies are a success and the troupe wins the contest. In the end, at the Person Scouts awards ceremony, aunt Kali reveals that the secret recipe contains insects, but everyone continues eating the cookies anyway.
3c	"A Dumb Wish"	Brian Hogan	Paul McEvoy	Paul McEvoy	October 12, 2001 (2001-10-12)	TBA
While Spring cleaning in the middle of November, Billy finds an old lamp in Grim's trunk. Despite Grim's warning about it being cursed, Billy shines the lamp anyway, releasing Grim's mother from inside. She tells Billy that she will grant him three wishes. Billy's first wish is used up when he wishes to know what to wish for. After Billy and Grim argue about who gets to make the next wish, Mandy wishes they both would "shut up", and their lips are sealed with a zipper. Mandy decides to grant the last wish to whoever makes her the happiest. When the two fail to make her happy, Mandy wishes everyone in the world would go away, leaving Mandy the only person left on Earth.
4a	"Grim or Gregory?"	Brian Hogan	Story by : Gord Zajac	Shellie Kvilvang	July 26, 2002 (2002-07-26)	TBA
On Halloween, Billy, Mandy, and Grim go trick-or-treating. Grim mistakes a woman for Atrocia, the host of the all-night Halloween marathon on TV and goes to talk to her. Upon looking at her face, Grim realizes his mistake; however, the woman mistakes Grim for her son, Gregory, and takes him home. At the same time, Billy mistakes Gregory for Grim and he and Mandy take him with them. In the end, Billy and Mandy take Gregory back to his mother and Grim goes back with them.
4b	"Grim vs. Mom"	Brian Hogan	Story by : Gord Zajac	Alex Almaguer	July 19, 2002 (2002-07-19)	TBA
After having a nervous breakdown and leaving the house in the first episode, Billy's mother, Gladys, returns. She meets Grim again and, this time, she plans to destroy him once and for all. When Grim goes to the kitchen for a glass of water, Gladys attacks him and shatters his skeleton. In the end, Grim assures the kids that Gladys has won the battle but not the war.
4c	"Tastes Like Chicken"	Brian Hogan and John McIntyre	Story by : Gord Zajac	Mike Diederich	July 19, 2002 (2002-07-19)	TBA
With Irwin not answering the phone, Billy's parents missing and Mandy saying she wants "Billy for dinner", Billy and Grim assume Mandy is a cannibal who ate Billy's parents and friends. Looking for proof, Billy and Grim find tiki figures and arrangements for a celebration in Mandy's backyard. Ultimately, it is revealed that they are just celebrating Billy's birthday. Still, Mandy burps out Irwin's glasses, implying that Mandy ate Irwin, causing Billy to scream in terror.
5a	"Something Stupid This Way Comes"	John McIntyre and Robert Alvarez	Story by : Craig Lewis	Maxwell Atoms	July 26, 2002 (2002-07-26)	TBA
Nergal, the fiend from the center of the Earth, returns to the surface, bringing a carnival with him, trying once more to make friends with the surface dwellers. Billy tries to help Nergal make friends by being considerate, but Nergal fails to use his advice correctly. When Nergal is told that Grim was forced to be Billy and Mandy's friend-slave, Nergal then decides to force the world to be his friends by turning them into dark beings similar to him. In the end, Nergal turns Billy, Mandy, Grim, and even the viewer (thus breaking the fourth wall) into one before the episode ends.
5b	"A Grim Surprise"	John McIntyre and Robert Alvarez	Story by : Rob DeSales	John McIntyre	August 2, 2002 (2002-08-02)	TBA
Billy tells Grim to help him throw a surprise birthday party for Mandy. Then, a reluctant Grim helps Billy prepare a cake while keeping it a secret from Mandy. In the end, a somewhat surprised Mandy reveals that her birthday is not for five months, something that Billy already knew about, stating that makes it "a real surprise party."
5c	"Beasts & Barbarians"	Dave Brain	Story by : Gord Zajac	Michael Diederich	August 2, 2002 (2002-08-02)	TBA
Billy and Irwin have been playing their favorite video game, Beasts and Barbarians, for three days non-stop. In an attempt to stop their video game addiction, Grim transports them all to a real-life version of the game. Seeing as Billy and Irwin are still doing good in their quest, Grim increases the difficulty by manipulating the traps himself. In the end, Billy, Mandy, and Grim return home escaping from a giant cyclops, while Irwin remains trapped.
6a	"Billy's Growth Spurt"	Brian Hogan	Story by : Gord Zajac	Michael Diederich	October 4, 2002 (2002-10-04)	TBA
Billy eats too much junk food that makes him feel sick. Grim prepares him a remedy using his granny's recipe, but it causes a parasite to growing on Billy's back, which Billy names Yap-yap. Billy and Yap-yap continue eating junk food, so Mandy suggest to use the antidote to the original remedy. Eventually, Yap-yap, now looking like a smaller version of Billy, detaches himself from Billy and tries to escape from the antidote. In the end, Yap-yap drinks the antidote and is destroyed.
6b	"Hoss Delgado: Spectral Exterminator"	Brian Hogan	Story by : Gord Zajac	Brian Kindregan	August 9, 2002 (2002-08-09)	TBA
Billy, Mandy, and Grim go to the museum on a school trip. There, they meet Hoss Delgado, self-appointed hunter of the paranormal, who upon spotting Grim, tries to eliminate him. Subsequently, Grim and Delgado engage in a fight. Finally, Delgado quits hunting Grim when he realizes Billy and Mandy control him. In the end, Delgado continues his own adventures and is seen fighting a werewolf.
6c	"Tickle Me Mandy"	Brian Hogan	Story by : Gord Zajac	Mucci Fassett	October 11, 2002 (2002-10-11)	TBA
Mandy and her parents leave the city for a day, which makes Billy feel lonely. Then, Grim uses his supernatural powers to create a fake Mandy with pieces of dolls and toys for Billy to play with. However, the "new" Mandy is too aggressive with Billy, and he starts fearing her. The next day, the real Mandy returns home, and promptly destroys the new Mandy while on a see-saw.
7a	"Billy & The Bully"	John McIntyre and Robert Alvarez	Story by : Gord Zajac	Brett Varon	October 4, 2002 (2002-10-04)	TBA
Billy is constantly provoked by a bully named Sperg and runs over to Grim for help.
7b	"To Eris Human"	Dave Brain	Story by : Gord Zajac	Chris Savino	August 9, 2002 (2002-08-09)	TBA
While going to the shopping mall with Billy and Mandy, Grim spots the seductive Eris, the cunning Goddess of Chaos and Discord, and tries to ask her out. However, Eris is not interested in the skinless Grim, but in the muscular Adonis. Then, Eris invites Mandy to join her in creating chaos using the Apple of Discord. Although initially they get along, Eris pulls a prank on Mandy, who subsequently tries to get revenge. In the end, Mandy fools Eris into thinking that Adonis is in the movie theater and Eris accidentally kisses Grim, who says that he will never wash his left cheek again.
7c	"Big Trouble in Billy's Basement"	Robert Alvarez and John McIntyre	Story by : Gord Zajac	Chris McCulloch	October 11, 2002 (2002-10-11)	TBA
After taking the Underworld's "Bad Book" from Grim, Billy becomes possessed by an evil presence. Then, Billy steals Grim's scythe, and uses it to open a portal to summon Yog-Sothoth. In consequence, Mandy calls for Hoss Delgado to battle Billy. It is revealed that the portal can only be sealed by throwing the book into it. As Billy eats the book, Mandy throws Billy himself into the portal, restoring everything to normal. Seconds later, a portal opens up and Billy comes out and says they didn't want him there.
8a	"Battle of the Bands"	Robert Alvarez	Story by : Craig Lewis	Brett Varon	August 1, 2003 (2003-08-01)	October 29, 2003
Billy wants to join Sperg's garage band, "Purple Filth", and take part in the upcoming battle of the bands. After witnessing Grim's prowess with the electric guitar, Sperg invites Grim instead. Billy's dad, adopting the rock and roll persona of "Mogar", decides he and Billy should go to the contest to make a surprise appearance. Billy impresses the audience with his armpit sounds. The song featured is "Darkness", composed by SPF-1000's David Ivy specifically for this episode.
8b	"Little Rock of Horrors"	Robert Alvarez	Story by : Gord Zajac	Maxwell Atoms	October 18, 2002 (2002-10-18)	TBA
In this musical episode, Billy befriends a singing brain-eating meteor (voiced by Voltaire) that falls from the sky after when everyone doesn't want to play with him because they are busy. With Billy's help, the creature grows bigger and eventually eats the brains of all people in Endsville (turning them into zombies with glowing green eyes). The last brain he eats is Mandy's, which results in the creature transforming into a pink, brain-eating Mandy meteor. The song featured is "BRAINS!", composed by goth artist Voltaire specifically for this episode.
8c	"Dream a Little Dream"	Dave Brain	Story by : Gord Zajac	Michael Diederich	October 18, 2002 (2002-10-18)	TBA
Billy, Mandy, and Grim eat moldy pizza leftovers and after falling asleep, they have nightmares. Billy dreams of cute bunnies which turn into horrific and deadly monsters; Grim dreams of an endless number of bossy Mandys; Mandy dreams of being pulled into a volcano and then commanding demons at the rhythm of music. In the end, Mandy reveals that her dream was actually very pleasant and she eats the last slice of the rotten pizza.
9a	"Toadblatt's School of Sorcery"	Robert Alvarez	Story by : Ben Spergel	Mike Diederich and Maxwell Atoms	June 13, 2003 (2003-06-13)	October 25, 2003
Grim sends Billy and Mandy to a sorcery school so the latter duo could avoid boring summer camps they were supposed to go to. The sorcery school is owned by Dean Toadblatt, an anthropomorphic frog. Billy and Mandy are sent to the most hated house of the school, Weaselthorpe, while Grim becomes a prefect for a more loved house, Gunderstank. Billy and Mandy team up with boy wizard Nigel Planter to sabotage Gunderstank's hopes of winning the house championship. Planter takes all the credit for the sabotage (which was Mandy's idea), but he is punished once he is found out by Toadblatt.
9b	"Educating Grim"	Juli Hashiguchi	Story by : Rachael MacFarlane	Brett Varon	June 13, 2003 (2003-06-13)	October 25, 2003
Billy and Mandy take a reluctant Grim to school with them. Mandy's nemesis, Mindy, befriends Grim to annoy Mandy and Billy calls for their other friend, who is Abraham Lincoln. Mandy devises a plan in which Mindy ditches Grim, and keeps Abraham as her friend instead.
9c	"It's Hokey Mon!"	John McIntyre and Robert Alvarez	Story by : Gord Zajac	Mike Diederich	June 13, 2003 (2003-06-13)	October 20, 2003
After watching Billy and Irwin play with their "Hokey Monsters" cards, Grim makes the monsters come to life. Soon, all the other kids want their own cards to be real too, and the city is soon under attack by a multitude of Hokey Monsters. To end the mayhem, Mandy draws her own card, Mandy's Monster, which defeats all the other monsters by turning them into toast.
10a	"Night of the Living Grim"	Juli Hashiguchi	Story by : Gord Zajac	Spencer Laudiero	June 20, 2003 (2003-06-20)	October 28, 2003
Grim is lying sick in bed with "Encroaching Doom Syndrome". The Underworld doctors are not able to help Grim, and he becomes a human being. Back in Endsville, Grim seems attractive to women, but he ends up being punched by jealous boyfriends, especially Billy's dad Harold. Grim covers himself in the mucus that he produced when he was sick and becomes a skeleton again, and Billy tries it too.
10b–10c	"Brown Evil"	Robert Alvarez	Story by : Gord Zajac	Paul McEvoy	June 20, 2003 (2003-06-20)	October 23, 2003
		Pat Shinagawa
Part 1: Taking inspiration from his Pat the Baker video game, Billy decides to bake chocolate brownies. Billy uses "Evil Powder" from Grim's old trunk instead of salt, and the resultant brownies stink. Mandy tells Grim to get rid of the brownies, and he reluctantly does, but he also stores some of them in his skull. Soon, the stench of the brownies spreads through the world and starts resurrecting dead people, animals, and even food, as zombies. Part 2: Billy and Hoss Delgado, spectral exterminator, team up to destroy all the zombies that congregate outside the house, but the zombies reassemble into a bigger zombie. Delgado realizes that the zombie is after the brownies that Grim has in his skull, so Delgado and Grim battle furiously for them. The zombie eats the remaining brownies and falls apart.
11a	"Mandy, the Merciless"	Pat Shinagawa	Story by : Gord Zajac	Alex Almaguer	June 27, 2003 (2003-06-27)	October 22, 2003
On a hot day when Billy, Mandy, and Irwin are bored, Grim uses a crystal ball to show them the future. In the distant future, Mandy has turned herself into a giant worm-like creature to be immortal, and now rules the whole world. Mandy gives false information to a clone of Billy to capture the members of a resistance that try to defeat her.
11b	"Creating Chaos"	Pat Shinagawa	Story by : Gord Zajac	Brett Varon	June 27, 2003 (2003-06-27)	October 26, 2003
When Billy, Mandy, and Grim go fishing, Eris, the goddess of chaos, gets Billy to help her use the Apple of Discord to create chaos. Instead of using the apple, Billy becomes distracted with his own idiotic errands, leading Eris to go insane. Billy finally decides to start creating chaos, but Eris is already too altered that she runs away.
11c	"The Really Odd Couple"	John McIntyre and Randy Myers	Story by : Gord Zajac	Mucci Fassett	June 27, 2003 (2003-06-27)	October 22, 2003
Billy accidentally sets off a powerful stink bomb in Mandy's house and, while the house is being disinfected and fumigated, Mandy's family goes to live with Billy's. Billy and Mandy have a dispute over how to split Billy's room, prompting Grim to intervene. Mandy takes over the entire room, and imprisons Billy inside a brick wall with his mouth gagged by a dark red handkerchief.
12a	"Who Killed Who?"	Pat Shinagawa, John McIntyre, and Randy Myers	Story by : Gord Zajac	Paul McEvoy	July 4, 2003 (2003-07-04)	October 27, 2003
After excluding Mandy from their board game "Who Killed Who?" for being a girl, Billy and Irwin mistakenly throw their dice into the backyard of a haunted house. Grim warns them about the ghost of Mrs. Doolin, a lady that lived there. Mandy dares them to go retrieve the dice, and she befriends Mrs. Doolin, who is alive and well, and who says that all the stories told about her (that anything that went beyond her fence into her garden never came back) are inventions from Grim, whom she beat long time ago at a staring contest. Fearing for Mandy's life, Billy also ventures into the house, but Mrs. Doolin and Mandy scare him away by posing as ghosts. It appears that Mrs. Doolin is in fact a ghost, and when she meant "beating Grim", it meant that she "beaten death".
12b	"Tween Wolf"	Pat Shinagawa	Story by : Gord Zajac	Mucci Fassett	July 4, 2003 (2003-07-04)	October 20, 2003
After when Grim fails to pull a werewolf out of his hat, Irwin is bitten by said werewolf. Billy takes Irwin as his new pet dog, naming him Sprinkles, and enters him in the Endsville Dog Show to compete against Mandy's dog, Saliva. At the contest, Sprinkles is about to win, so Grim releases a "were-flea" whose bite causes the werewolf to revert to a naked Irwin.
13a	"Grim in Love"	John McIntyre and Robert Alvarez	Story by : Gord Zajac	Brett Varon	July 11, 2003 (2003-07-11)	October 21, 2003
When Billy, Mandy, and Grim go to the beach, Grim falls in love with a goth woman named Malaria. Grim is having a good time with his girlfriend, but Mandy assures him that will change when he tells her that he is not human. In the following date, Grim demonstrates his supernatural powers while dancing and, as predicted, Malaria leaves in panic.
13b	"Crushed"	John McIntyre and Robert Alvarez	Story by : Gord Zajac	Brett Varon	July 11, 2003 (2003-07-11)	October 28, 2003
At school, Mandy rejects Irwin's invitation to go to the school dance with him. Billy introduces his foreign and mysterious new friend, Piff, and Mandy becomes desperate when she realizes that she has developed a crush on him. Mandy asks Grim to cut her heart out to stop being in love, but Grim has a better idea and gives Mandy a makeover, turning her into a really seductive figure. Piff gets a crush on Mandy (the same way Irwin had gotten before), who takes the opportunity to brutally turn him down.
13c	"Love is "Evol" Spelled Backwards"	Juli Hashiguchi	Story by : Craig Lewis	Paul McEvoy	July 11, 2003 (2003-07-11)	October 21, 2003
It's Valentine's Day and Nergal, the fiend living in Earth's core, appears in Billy's house to court Billy's spinster aunt Sis. Billy tries ruining Nergal's date, to avoid becoming his nephew. Although initially Sis does not show interest in Nergal, she changes her mind when Nergal is stung by bees and she sees his "dance moves". Aunt Sis accepts Nergal's marriage proposal and accompanies him back to the center of the Earth.
14a	"The Crawling Niceness"	John McIntyre and Robert Alvarez	Story by : Maxwell Atoms	Maxwell Atoms	July 18, 2003 (2003-07-18)	October 30, 2003
Billy takes a big egg found in Grim's trunk and hatches it expecting a duck. Instead, Jeff the Spider is born, who considers Billy his father. Despite Jeff trying to please Billy in any possible way, Billy is terrified of Jeff and wants him squished. The exterminator chose not to squish Jeff because he is a nice bug.
14b	"Smarten Up!"	John McIntyre and Robert Alvarez	Story by : Gord Zajac	David Feiss	July 18, 2003 (2003-07-18)	October 24, 2003
Billy is worried about failing an upcoming Math test, so Grim gives him a "bookworm", which will make him much smarter. Milkshakes, Billy's cat, eats the worm instead, and is forced to tutor Billy. Billy is still an idiot in the end.
14c	"The Grim Show"	John McIntyre and Robert Alvarez	Story by : Craig Lewis	Trevor Wall	July 18, 2003 (2003-07-18)	October 26, 2003
Grim is upset after his favorite show, Atrocia's Late Night Atrocities, is cancelled. He goes to the TV station and using his powers, turns the studio into a creepier place and becomes the host of the Grim Show. Grim's success on TV is interrupted when Mandy tells him he has neglected to do her chores. Billy and Mandy go to the TV station and show embarrassing footage of Grim at home.
15a	"Son of Nergal"	Robert Alvarez	Story by : Gord Zajac	Paul McEvoy	July 25, 2003 (2003-07-25)	October 27, 2003
Billy and Mandy are sent to "Winter Camp", where they meet Nergal's son, Nergal Jr. Just like his father, Junior tries making friends, although not in the best way possible. Junior attacks the campers, freezes them and, using his shape-shifting abilities, takes over their appearances. Billy decides to be Junior's friend, but he is scared away at the moment Junior shows him his true form.
15b	"Sister Grim"	John McIntyre and Juli Hashiguchi	Story by : Gord Zajac	Brett Varon	July 25, 2003 (2003-07-25)	October 31, 2003
After being accidentally hit by Billy, Grim lands in a can of white paint in a remote convent. Due to his appearance, still with the can in his head, Grim is mistaken for "Sister Big Mamma" by little cherubic nuns. Grim has a great time with the friendly nuns, until Billy and Mandy come looking for him. When the nuns realize the truth about Grim they get angry at him, but also help him go back home by sending him flying away with another punch.
15c	"Go-Kart 3000!"	John McIntyre and Randy Myers	Story by : Gord Zajac	Michael Diederich	July 25, 2003 (2003-07-25)	October 24, 2003
When Billy and Irwin exclude Mandy and Grim from helping them build a go-kart to enter the Annual Endsville Go-Kart Competition, the latter two decide to build their own. Billy-Irwin, and Mandy-Grim compete against Mindy, Sperg, and a mystery racer (Pud'n). Mindy gets stuck in highway traffic, Billy-Irwin's car is destroyed, Sperg and Grim mutually prevent each other from winning, and Pud'n wins in his little red wagon.
16a	"Five O' Clock Shadows"	Juli Hashiguchi	Story by : Brett Varon	Brett Varon	October 22, 2004 (2004-10-22)	October 31, 2004
16b	"Terror of the Black Knight"	Juli Hashiguchi	Story by : Craig Lewis	Alex Almaguer	August 1, 2003 (2003-08-01)	October 29, 2003
After being impressed by Irwin's realistic armor at the medieval fair, Billy wishes for a fancy armor too. Grim gives him the "Cursed Suit of the Black Knight". When Billy needs to go to the bathroom, the curse is revealed to be that the armor cannot be taken off until the person wearing it beats someone in a competition. Billy desperately tries to defeat other people at various contests, but fails to come out victorious. He defeats Mandy at a breakdance contest in which Mandy decided not to participate, but he does not need to go to the bathroom anymore.
17a	"Grim for a Day"	Robert Alvarez	Story by : Craig Lewis	Paul McEvoy	August 15, 2003 (2003-08-15)	October 31, 2003
After a lousy night for Grim, Billy and Grim argue about who has the hardest time, the kid or the Reaper of the Souls. Mandy shouted at Grim and Billy to "SHUT UP!" first, but then she proposes they switch places for the day to find out. Grim seems to be having a good time, acting like a silly kid, while Billy is bored waiting for his old victim, Mr. Voorhees, to open the door. Billy transforms into a short skeleton, while Grim transforms into a taller version of Billy.
17b	"Chicken Ball Z"	Juli Hashiguchi	Story by : Ben Spergel	Matt Sullivan	August 15, 2003 (2003-08-15)	October 30, 2003
17c	"The Halls of Time"	John McIntyre and Randy Myers	Story by : Gord Zajac	Mike Diederich	August 1, 2003 (2003-08-01)	October 31, 2003
After missing a school trip, Grim takes Billy, Mandy, and Irwin to the "Halls of Time" for a tour. There, Billy and Irwin mess with the hourglasses that symbolize each person's lifespan. When they leave, they accidentally leave their own hourglasses, including Grim's, upside down, resulting in the group getting younger as time passes. Grim allows the kids to disappear by going before birth, but he cannot restore his own hourglass to its correct position and he disappears too. Note: When this episode is paired with "Terror of the Black Knight" and "Battle of the Bands" on its first airing as well as subsequent airings, Evil Con Carne's "Max Courage!" would be airing in its place between "Grim for a Day" and "Chicken Ball Z".
18	"Billy & Mandy's Jacked-Up Halloween"	Juli Hashiguchi and Robert Alvarez	Story by : Maxwell Atoms, Brett Varon, and Paul McEvoy	Brett Varon and Maxwell Atoms	October 1, 2003 (2003-10-01)	November 1, 2003
Billy, Mandy, and Grim go trick-or-treating for Halloween, but Irwin is left behind because he needs a scarier costume. After pulling a trick on an old lady, and getting some candies, Grim tells the story of why people pull pranks, which he was partially responsible for. He tells about Jack (voiced by Wayne Knight), a prankster of the old Endsville who just never knew when to stop. One day, the citizens decided to punish him for his constant pranks, and they pulled a prank on the queen, but signed it "From: Jack"; in consequence, the angry queen sent a knight to kill Jack. When Grim went for Jack's soul, Jack stole his scythe. In return for his scythe, Grim promised Jack eternal life, but after closing the deal, Grim takes his scythe and cuts Jack's head off, showing that no one will ever see his face again. Afterwards, Jack decided to use a pumpkin for a head, becoming Jack O'Lantern the Mandrill Baboon and Sloth, and, suffering from the loss of his real head and learning his lesson about pulling pranks too far and whom he does them to, every Halloween he goes out to pull pranks on the citizens of Endsville, and waits 364 more days a year until next Halloween in a solitary mode in his own house. After hearing the story, Billy splits from the group and finds Jack's house downtown. Jack realizes Billy is carrying the actual Reaper's scythe, so he takes it from him and uses it to open the gates of the Underworld and bring forth ghosts, which cause havoc in the city. Jack then plans to get revenge on Grim by cutting his head off which, being cut with the Reaper's scythe, will stay off "forever". To stop Jack from carrying on with his vengeance, Mandy sets up a series of pranks for him. The pranks affect Irwin instead, causing major laughter from Jack and his ghouls, which explode and return to the Underworld. Grim recovers his scythe and sends Jack to the Underworld too.

Home releases

The Grim Adventures of Billy & Mandy: Season 1 was released on Region 1 DVD on September 18, 2007. It contains the episodes "Meet the Reaper" – "Love is 'Evol' Spelled Backwards" and "Battle of the Bands". Along with bonus features, it also includes the Evil Con Carne episodes "Evil Con Carne", "Emotional Skarr", "Evil Goes Wild", "Evil on Trial", and "The Smell of Vengeance".

Other releases including The Grim Adventures of Billy & Mandy season one episodes:

• "Billy and Mandy's Jacked-Up Halloween" – Cartoon Network Halloween: 9 Creepy Cartoon Capers (August 10, 2004)
• "Son of Nergal" – Cartoon Network Christmas: Yuletide Follies (October 5, 2004)
• "Night of the Living Grim" – Cartoon Network Halloween 2: Grossest Halloween Ever (August 9, 2005)
• "Crushed!" – Codename: Kids Next Door: Sooper Hugest Missions: File Two (August 23, 2005)
• "Battle of the Bands" – Cartoon Network: Christmas Rocks (October 4, 2005)
• The first thirteen episodes and "Battle of the Bands" – 4 Kid Favorites: The Hall of Fame Collection Vol. 3 (June 23, 2015)