Billy's pet hamster, Mr. Snuggles, celebrates his 10th birthday, so the Grim Reaper comes for him. However, Mandy, Billy's friend, is reluctant in all...
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 da...
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 t...
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...
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...
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 ...
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 lan...
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. Howev...
While Spring cleaning in the middle of November, Billy takes an old, cursed lamp from Grim's trunk. When he gives it a rub, he releases the curse Grim...
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...
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 w...
It's 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 ...
Nergal, the fiend from the center of the Earth, returns to the surface, emerging a carnival with him, trying once more to make friends. In the followi...
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 fr...
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 ad...
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 Gr...
While going to the shopping mall with Billy and Mandy, Grim spots the beautiful Eris, the goddess of discord and chaos, and tries to ask her out. Howe...
Billy eats too much junk food that makes him feel sick. Grim prepares him a remedy using his granny's recipe, but this medicine makes a parasite to st...
Billy is constantly provoked by a bully named Sperg and runs over to Grim for help.
After taking the Underworld's "Bad Book" from Grim, Billy becomes possessed by an evil entity. Then, Billy steals Grim's scythe, and uses it to open a...
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 pie...
In this musical episode, which pays homage to Little Shop of Horrors, Billy befriends a singing brain-eating meteor (voiced by Voltaire) that falls fr...
Billy, Mandy, and Grim eat moldy pizza leftovers, and after falling asleep, they have nightmares. Billy dreams of cute bunnies which turn into monster...
A headless man from Grim's past uses Billy to steal Grim's scythe.
At a father-and-son picnic, Billy re-encounters with his spider "son", Jeff, in a dirty bathroom. Once again, Jeff tries to make Billy love him as a t...
When Billy crashes his bicycle, he obtains a free tricycle from a mysterious boy in a supernatural porta-potty. While Billy loves his tricycle, which ...
After spilling salt in a restaurant, and not throwing salt over his left shoulder, Billy starts having an unusual amount of extremely bad luck. The ne...
Billy, Mandy and Grim go to the beach where Grim falls asleep and Billy buries him in sand. When they leave, Billy only takes Grim's skull, leaving Gr...
After he turns down his dad's invitation to go fishing, Billy gets a tiny, weakling, pet fish, which he names Little Porkchop. To make Billy happier, ...
General Skarr buys a home in Endsville and becomes Billy's neighbor. After Skarr invites Billy into his new house, Billy mentions Grim's scythe as ,he...
Lord Pain, a fearsome warrior from the Plain of Eternal Suffering, appears in Billy's house looking to serve his master, Grim. Lord Pain is put to cle...
In this short, set in the Stone Age, a child version of Grim undertakes his first assignments as the Grim Reaper. When he goes to visit a cave witch, ...
When Mindy mocks Mandy's dumb and coward dog, Saliva, Mandy decides to train her dog to be meaner. After Grim keeps mentioning his own dog, Cerberus, ...
After Billy eats 19 creme-filled Atomic Frenzy Cakes he cannot sleep and wants Mandy to read him a bedtime story. Mandy, Billy and Grim each tell a st...
When Billy ruins his eyes by playing too many video games and looking directly into the Sun, Mandy and Grim suggest he see an ophthalmologist. When Bi...
When Billy, Mandy and Grim go playing golf, they encounter boy wizard Nigel Planter again, who is there hiding from the dark wizard Lord Moldybutt. Th...
When Billy and Mandy are utterly bored, Grim takes them to Underworld's "Circus of Fear". The ringleader, Dr. Fear, notices Billy and Mandy, and tries...
After failing to scare a fifteen-year-old, the Boogeyman decides to visit his old middle-school victim, Grim. Grim remembers how Boogie used to be a b...
As Billy walks into the woods to have a picnic, Yogi and a giant, feral version of Boo-Boo (from The Yogi Bear Show) come to steal his basket, and he ...
While going to a science museum, Billy and Mandy's school bus breaks down in the middle of the desert. After digging for fossils, Billy, Mandy and Gri...
Billy's first cousin from the center of the Earth, Nergal Jr. goes to school for the first time, but he is worried that people may not like him. Soon ...
After watching a TV show, starring Captain Heifer and his Heifer Farms Brand Yogurt, Billy asks Grim to turn him into a superhero with the power of sq...
Trying to get revenge at Mandy for bossing them all the time, Billy and Grim put her in the "Mask of the Beast". Mandy must be nice and friendly while...
When Billy sees his father shaving, he decides having a beard is cool and buys "Hair Raiser Tonique", a hair-growing formula. Grim casts a spell on th...
After being bullied again by Sperg, Billy asks Grim to shrink him to enter Mandy's head to steal her "nerve". After Billy swallows the raw nerve, a po...
When Billy forgets to do his history homework, Grim gives him a universal remote control to alter time and space so he can go back in time and finish ...
During a thunderstorm, a lightning bolt hits Grim's scythe, transporting Billy to Asgard, land of the Norse gods. Mandy and Grim go searching for him,...
Grim is annoyed by Billy who thinks that a shadow is following him. Grim takes Billy and Mandy to the Shadows' World, where their opposites live. Grim...
After Billy wakes up from another nightmare involving clowns, he is more terrified than ever towards them, so Mandy and Grim try to cure him of this c...
Thinking that the world is chaotic enough as it is, Eris, the goddess of chaos, decides to quit chaos to work at a hamburger restaurant. She entrusts ...
When Billy and Mandy have a brief fight, Billy says he never wants to speak to Mandy again. The next day, Billy is over his grudge, but Mandy has alre...
When a doctor is unable to cure Sperg of his severe case of acne, Sperg goes to see a fortune teller that deals with skin problems. Following a Burmes...
While reading an Underworld comic book, Billy finds an advertisement for "Chocolate Sailors", a delicious chocolate candy-which being Underworld candi...
When Billy has a loose tooth he cannot wait for the Tooth Fairy to appear to give him money. Mandy, who does not believe in the Tooth Fairy, asks Sper...
When Billy hangs out at Irwin's house, he finds a living mummy in the bathroom. Seeing as Irwin gets nervous, and as Billy has never met Irwin's mothe...
Thanks to Mandy, Billy decides to get rid of his "Dinobonoid" action figures thinking he is too old for them. Grim makes the toys come to life, and sh...
At school, Billy, Mandy, and Irwin look for a club to join. Irwin plans to join the Macrame club to meet girls; Billy inquires on the Junior CIA club,...
When Billy and Mandy's school is preparing for a big game, Mindy entrusts the care of the school's mascot, Fluffy Cat, to Billy, to protect him from b...
As Billy is tired of all the rules in his house, he cannot resist the urge to try his father's new motorcycle. The motorcycle breaks down, and Billy a...
After Billy's baseball team loses badly against Mindy's, Grim decides to coach them. Mandy is not allowed on the team, as Billy is reluctant to let gi...
While at Sassy Cat Land, the theme park dedicated to Sassy Cat (and to ridiculously long lines), Billy, Mandy, and Grim stumble upon a closed attracti...
After a trip to the mall, Mandy becomes the spokesperson for Happy Huggy Stuffy Bears, a new stuffed toy in town. After the success of her commercial,...
When Billy finally gets a "secret decoder ring" in his Blasto Bits cereal, he receives a holographic message from a strange creature who speaks about ...
One night a strange odor travels through the city, prompting the noses of all the people, including Billy's, to follow it. The next night, Mandy, who ...
When Billy goes into the mud for the fifth time in the day while wearing his white tuxedo before a wedding, Grim tries to figure out why Billy is so s...
After Grim's robe comes out of the washing machine, Billy and Mandy find Thromnambular, a talking skull with ruby eyes and a number nine imprinted on ...
When Billy gets the opportunity to adopt one of four dogs, he says he wants them all. Grim uses his scythe to magically combine the dogs and create Bi...
To raise money to buy Sea-Critters (similar to Sea-Monkeys), Billy has a garage sale where he sells Grim's scythe to Irwin for less than two cents. Wi...
When Billy gets under his house's foundation, he encounters again his "son", Jeff the Spider, who has just laid eggs. Jeff tries to make things right ...
After seeing Billy, Mandy and Grim battling a strange creature, Irwin again feels rejected by Mandy. Hoss Delgado, spectral exterminator, appears to h...
After Grim has a nice dream, a nightmare escapes the back of his head in the shape of a supernatural, invisible duck that makes farting noises. The du...
After being utterly bored of watching the same movie 60 times in a row, Grim takes Billy and Mandy to "Underworld Video" where they rent "The Legend o...
Billy and Mandy find a supernatural zipper from Grim's robe, and while Billy uses it to create mischief, Mandy gets herself in a sticky situation.
When Billy jumps into a supernatural puddle (a Cosmic Sinkhole, according to Grim), it takes him to the home of Granny Applecheeks, who wants to bake ...
At school it is time for the "Presidents Fitness Test", but Billy is absolutely unfit for exercise. On the other hand, Nergal Junior uses his shape-sh...
After Grim's scythe fails to open a portal, he decides to sharpen it, but the blade breaks. Billy, Mandy and Grim go to the Underworld to meet F (a pa...
When Billy buys a new cereal, a phoenix emerges from the box and attaches to his head, annoying everybody. Since the phoenix cannot be removed because...
When Billy desperately wants chewing gum at school, Grim gives him a bottomless gumball machine, but warns him not to swallow the gum. Billy ignores G...
When Billy is accepted to Mrs. Pollywinkle's dancing academy, his father tries to persuade him to forget about dancing because of his own bad experien...
When Grim misuses his powers to play bowling with asteroids, he is taken to the Underworld court and sentenced to 50 hours of community service. At a ...
When it's scurvy-prevention day at school, Mindy parades in her float in anticipation for the Little Miss Scurvy beauty pageant, and she insults Mandy...
When Billy's parents are attacked by an anaconda, Billy suggest visiting boy wizard Nigel Planter, because he can talk to snakes. Planter in fact does...
When Billy's parents leave for their second honeymoon, Billy is left alone at the worst possible moment, since he has invited Principal Goodvibes over...
Then Billy's mom, discovers crow's feet on her face, she panics and does not want to leave the bathroom. As Grim needs to use the bathroom, he uses hi...
When Billy, Mandy and Grim notice things have been disappearing in the house, they set out to investigate using a supernatural detector. They find the...
When the mall's surveillance cameras capture Grim's silhouette attacking endangered owls, a naturalist named Corey Nebraska blames Grim for the attack...
When Nergal goes to visit Billy's family (his in-laws) for the weekend, he ends up staying with them over a year. When Billy finally asks his uncle to...
As Billy desires to be "cool" like Sperg, he has an ectoplasmic manifestation coming out of his mouth. The ectoplasm grows full size and turns out to ...
As Grim watches the entire season of "My Troubled Pony" (parodying My Little Pony), he learns from Mandy that the show was cancelled and does not have...
When Billy and Irwin start making prank calls, everybody knows that Billy is behind the calls because every telephone has a caller ID. While Billy sea...
The day before Christmas, Billy, Mandy and Grim go to the shopping mall, where Mandy complains that Santa Claus is just an invention from corporations...
When Billy, Mandy and Grim go to the beach, Billy is swallowed by a whale known as Blubbery Joe, which also houses in her stomach Mister Geppetto and ...
When Mandy and Grim tell Billy to quit watching TV and follow his life dreams, Billy gets into a chicken costume and decides to become a world famous ...
When Billy's dad gets a promotion at his job, he tells his family they are going to move to another town, starting a dispute between Billy and Mandy o...
When Billy decides he wants to grow up to be like Grim, he says nothing will stand in the way of their friendship. They meet a girl named Blandy, who ...
Billy, Mandy and Grim visit Mighty Moe, an old man who has discovered the secret to add extra years to his lifespan: a good diet and exercise. Mighty ...
When Billy digs his front yard he finds a frozen caveman, who is actually Fred Flintstone (from The Flintstones), but whom Billy names Jake Steele. Bi...
When Billy and Irwin want to watch classic giant monsters movies, Grim decides to take them to Japan to see real monsters. They meet the turtle-like C...
When Billy and Irwin are yet again bullied by Sperg, they decide to play for the school's football team so they are not bullied anymore. During practi...
When Billy gets his kite stuck in a tree, he starts throwing objects at it to knock it down, including Mandy and a group of three boy scouts, but all ...
When General Skarr tries to get rid of a weed in his otherwise perfect garden, he asks Grim to use his scythe to do the job. Billy drives a lawnmower ...
When Mandy and Grim go to the warehouse store, Mandy notices that everything seems to be in order, lacking any presence of chaos. Hoss Delgado, spectr...
When Billy goes to visit his maternal grandmother and Mandy decides to have the day for herself, Grim finds himself free of the kids to do whatever he...
There is a new student in the school, named Dora (parodying Dora the Explorer), who insists on getting people to open her lunch box. Mandy befriends D...
When Billy destroys Grim's favorite childhood toy, Fancy Jake, Grim feels devastated and wishes he had never lost the limbo game that made him become ...
As Billy sees Hoss Delgado's manliness is action again, Billy wishes to grow up to be a hero like him. Grim tells Billy that in older times an evident...
When Grim decides to visit again his childhood idol, the aged king of the vampires, Dracula, the latter suggest they drive to an early bird buffet, on...
As Billy and Mandy celebrate Father's Day, Grim becomes very depressed that he sits inside Billy's closet only listening to country rock music. Grim e...
As Mandy returns from Billy's house, it is evident that Mandy's parents are extremely afraid of their daughter and her iron fist rule over them. Unabl...
When Mandy says even a trained monkey is more competent to do cleaning chores than Grim, and would complain less, Grim makes Dickie Galoot, a monkey a...
At a school fair, Grim's scythe accidentally transforms the dull Principal Goodvibes and his hippopotamus into gangster rappers, Goodvibes now calling...
When Billy finds his "son" Jeff the Spider lying in his bed with "Spider Pox", he goes to Mandy for help to get rid of the giant spider. While ignorin...
As Grim appears in an Underworld TV commercial for "Big Move" laxative pills, an accompanying contest promises a day with the famous Grim Reaper to th...
As Billy notices Mandy and Grim's usual negative attitude, he wishes they were in a magical land of happiness, so Grim transports them to an enchanted...
As Billy, Mandy, Grim, and Irwin hang from a rope about to be eaten by a giant sea serpent, Irwin wonders how they came into that trouble. Billy and G...
As Billy behaves more reckless than ever and cannot stop breaking everything in sight, Mandy thinks he should go some place where he can release all h...
When Grim leaves the house to meet someone he met on the internet, Billy looks inside Grim's trunk for something to entertain himself. Billy finds a m...
As Billy realizes the three geeks of the Secret Snake Club get doctor's notes to avoid Physical Education (P.E.) class, he wants to know their secret ...
When Billy, Mandy and Grim attend an Ancient Egypt exhibit at the museum, they meet with Irwin who explains that, as his mother is a mummy, they are v...
When Billy fails an important test, the result of which will go into his permanent record, he asks Grim to magically alter his grade from an "F" to an...
After watching the Unsolvable Mysteries TV show, Grim realizes he forgot a million years ago to reap the Abominable Snowman living in the Himalayas. B...
When Nergal comes to tell the guys about his new pizza joint, Grim thinks he can do better by using his Granny's recipe. A pizza war ensues between Ne...
After Billy, Mandy and Grim are disappointed with the Sassy Cat amusement park submarine attraction, Grim uses his powers to take them to the bottom o...
As General Skarr is once again annoyed by Billy, Hector Con Carne and Major Dr. Ghastly arrive in his house with the intention of luring him back to t...
As General Skarr has trouble finding a job, the recruiter tells him to attend anger management classes if he wants to work again. Skarr finds out Mand...
When Mandy finds Billy playing with Grim's gigantic dog, Cerberus, she tells Grim to keep Billy under tight control because she needs a good night of ...
When Billy, Mandy and Grim once again go to the beach, Grim warns Billy to avoid swimming too far, because the "undertoad", a frog-like creature, will...
When Irwin lacks the courage to ask Mandy to go with him to the Valentine's Day school dance, he tells Nergal Jr. to do it for him. Mandy mistakes Jun...
When Billy accidentally food-poisons Miss Butterbean, Principal Goodvibes offers Grim the job of substitute teacher, which Grim accepts as now Billy a...
When Billy is sent to bed after playing with his Dr. Brainiac action figure, he wishes he had an adventure. He notices a strange light outside and wan...
When vampire hunter Lionel Van Helsing prepares to kill Dracula, Billy, Mandy, and Grim arrive to stop him since Dracula is just senile and harmless. ...
As Billy, Mandy, and Irwin need to write a school report on tall tales, Grim tells outrageous tall tales about Pecos Billy (based on Pecos Bill), Paul...
When Billy, Mandy and Grim go to a joke shop, they find the owner is former boy wizard Nigel Planter, who reveals that his powers diminished and was k...
When Grim cannot take any more abuse from Mandy, Billy tries using Grim's scythe to shrink her to mouse size. Instead of shrinking, Mandy becomes a gi...
When Billy's dad drives Billy, Mandy and Grim to the hamburger restaurant, they somehow end up in Mexico. There, the people are celebrating Dia de los...
When Billy starts taking pictures with a camera found in Grim's trunk, Grim tells him that is an Underworld's True-heart Camera, which shows the real ...
A scene of Endsville two weeks into the future shows a dystopian world ruled by the "Lord of Horror", who wields the all-powerful artifact known as "H...
On a rainy day, giant spiders appear in Billy and Mandy's school and start kidnapping the children one by one. Grim presumes this is somehow related t...
Billy, Irwin and Mandy go trick-or-treating on Halloween, and an evil marshmallow bunny attacks children with chocolate beasts.
While Billy's Dad is underwear shopping, Billy wears his dad's lucky pants, and accidently rips them with Grim's scythe. He calls Ed, Edd n Eddy, and ...
Billy looks into Grim's trunk and sees a monster and names it Myron. But when Billy brings Myron outside to his backyard, he gets eaten.
Billy's Dad forgot to buy Billy's present for his birthday again! Everytime Billy's Dad buys a present for Billy, he will get distracted by a "Rocket"...
Grim decides to make a cake for Billy's birthday, but he and Mandy end up making a Devil's Food cake that comes alive and began wrecking the kitchen. ...
Irwin finishes wrapping Billy's present and buys a huge present for Mandy as well. He decides it is not big enough so his dad decides to teach him how...
Dracula was heading for the bingo hall when he ran into Pud'n who was on his way to Billy's party. Dracula was insulted he was not invited to the part...
Billy blows out the candles off his cake and Dracula turns to leave, but Billy stops him and forces him to stay for games. They play Pictionary as he ...
Irwin has a dream sequence of taking Mandy out for the time of her life.
Irwin's grandmother, Tanya, embarrasses Irwin in an elevator ride with Mandy.
Irwin's future grandchild travels back in time to motivate modern-day Irwin to give Mandy a box of chocolates, but bully Sperg stands in the way.
Irwin wants to take Mandy out to dinner, and schemes to get money from the tooth fairy to pay for it.
Dracula participates in his senior home's self-defense course by role-playing as a "victim."
When the gang frees Thromnambular, the wish-granting skull, from a lamp, Grim and Mandy bicker over who gets to make the first wish.
When the Grim Reaper tries to take Billy's pet hamster, Mandy and Billy make a deal to save his life. So the Grim Reaper challenges the kids to a limb...
