Underfist: Halloween Bash, aka Underfist was a movie spin off from the Cartoon Network original series The Grim Adventures of Billy and Mandy.


It is Halloween, and now the Trick-or-Treating Service is going slow. Dracula only gives Irwin, Mandy, and Billy pennies. Then, Mindy calls Irwin a Loser, Ha-Ha! Then, Irwin decides to quit the holiday, and the movie seems like its going to end, with credits breaking the fourth wall, until Mindy calls out Wait a second, you idiot! I need your help!. Then, the movie goes really fast backwards to Irwin, where Mindy finally decides that Irwin is a someone because she needs someone to press a green gem on a spooky house because they're selling life-size chocolate bars. Irwin slowly pushes it with interrupting animation with foreshadowing. Then, after he presses the green gem crystal, a Vortex to the Underworld appears, a marshmallow bunny named Bunbun comes out, and his chocolate-bar soldiers come out of the Vortex with soda-rifles and hunting down the Trick-or-Treaters. The chocolate bars are about to destroy the town until Hoss Delgado comes out, and confronts the army. Then, Delgado's mommy comes out and tells Hoss to(No Mommy, Yes Mommy) play nice, while BunBun and the chocolate bars laugh that he's talking to his mommy. Then, Hoss uses his hand-gun to blow out the chocolate army, proceeding in destroying hundreds of them. BunBun later kidnaps Mindy while Irwin begs for help to save her. Several police cars rush until the chocolate bars aim ice cream at the police cars onto the roofs of houses. Later, chocolate army soldiers spray soda at Hoss Delgado, but soon, when they fight on one's lawn, it turns out that it is General Skarr who is the one to help Hoss destroy the chocolate bars because they ruined his #1 Trophy-Winning Lawn, using a robot-machine develop to fight the chocolate bars. Hoss later exclaims that the soda only affects him because they make his clothes all sticky gross.

Then, Fred Fredburger and Jeff the Spider consider of helping Hoss and Mr. Skarr. But first, Fred suggests that he spell his name: F-R-E-D-F-R-E-D-B-U-R-G-E-(aaahhhh)..Jeff: Is it R? Fred: R! Yes! Fred Fredburger! Then, a chocolate bar with a Love and Hate lollipop who fights Hoss Delgado has his hands eaten by Fred Fredburger because he likes lollipops, and the skeleton candy pieces are taken down by Jeff the Spider's webbing. Then, Irwin joins the four and take control of Delgado's car: Stick. After the joining and combination of the Underifst members, Hoss Delgado reveals that the new President of the United States has ordered all candy shop services in Endsville demolished in case the candy in the shops are evil as well. Then, the Stick vehicle drives into a Vortex covered in dirt under the crust in the Earth to follow BunBun. Hoss Delgado and Irwin fall into a Vortex leading into the Underworld Lair for Bunbun and the Halloween candies.

Later, Mindy reveals herself that now she transformed into a witch because she believes Irwin gave her mummy cooties, turning her into a witch. Hoss Delgado frustrated at Irwin for what he is, yells out that the boy who is half monster and half human lied to him twice when he told him he's not a monster, a vampire-mummy half with a human half together. Mindy the Witch later reveals that the President of the United States is trapped in a tall Ginger-Bread Prison Tower. While chanting out the success and good starting of the plan to take over the Trick-or-Treating plan started by Bunbun, Jeff is so worried, General Skarr is bored and angry, and Fred Fredburger is calm because he thinks there's no danger in the situation. While singing over a pot of green slime and hedorah used as a chemical to take over the world in Halloween night, Mindy chants out a song: Trick-or-Treater Eaters, where the Halloween candy monsters will become 10 times more powerful than ever and fill the pot with all her dirty and unusable waste into the bowl.

Hoss Delgado almost falls into a giant cup of chocolate until Irwin, who morphs into a vampire bat, saves him. Nergal's sandwich picnic is interrupted by Stick, where that time Irwin is able to climb the Gingerbread Tower and rescue the President of the United States, and it turns out to be Mandy, with no surprise. Mindy tries to destroy both Irwin and Mandy, until Jeff the Spider rescues them by webbing the two from the tower. General Skarr launches a giant missile fist into the chocolate cup, destroying the entire hot chocolate. Mindy and BunBun tries to destroy Stick by aiming jawbreakers at the body of the vehicle. After getting into the real world again, Mandy supports evidence that Trick-or-Treating is important to the world since kids eat Halloween-candy from taking over the world, found in several magazines about Halloween topic.

Each of the Underfist team members get their costumes from Grim, and now a green diamond destroys the metal hand from the Understick vehicle. Jeff is now seen wearing a diaper while BunBun returns with his mutated chocolate bar army. Hoss Delgado quits Underfist and later tries to go off on his own to save the world. Irwin battles Hoss Delgado from fighting him, while Jeff and Fred entertain the chocolate bars with the song I Don't Wanna Grow Up, showing how much they don't wanna grow up. Mindy shows up again, and transforms the entire chocolate army into a giant mutated monster with a pumpkin on its head.

After Hoss Delgado and Irwin rip off the hand of the monster, it steals the Stick hand, showing that he can plug a drill into the hand. Irwin, using his vampire/mummy powers rips off the Stick hand, and Hoss Delgado fires Billy at the monster to eat all the candy in it. Hoss later apologizes to Irwin for never trusting him just because he was a monster. He only didn't trust monsters because in his childhood, a boogeyman had haunted a miserable 30 years of his life, making him so scared every night for the next 30 years, and he only remembers after 16 years that he was wearing a hat.

Soon, BunBun returns with his entire chocolate pot with now General Skarr on his side. He later reveals all the naughty things he did to the team:

  • He made Mindy a witch by putting a witch worm into her hair, so that she can take him to Irwin.
  • He was the monster who haunted Hoss Delgado when he was a kid.
  • He made Jeff the Spider's dad, Billy, afraid of spiders by waving a toy spider in front of him when he was a baby.
  • He sawed off Fred Fredburger's tusks when he was sleeping.

Soon, General Skarr reveals that he tricked BunBun so that he can prevent him from pouring hot chocolate onto the Earth by kicking him into the pot, and everyone is saved. Mandy rewards each of the Underfist team members, and now Dracula complains he only got a penny for Halloween. Soon, a squid life form monster comes to destroy the Sun with his disgusting magic with his nephew. Underfist wastes no time and start to battle him. Throughout the ending credits, they spread their new song, Underfist, and show the future films what they'll appear in.


Voice actor Character
Tracy Braunstein Irwin
Peter Sallis Fred Fredburger
Earl Bowen Jeff The Spider
Rachel MacFarlane Mindy
Diedrich Bader Hoss Delgado
Mary Gibbs General Skarr
Grey DeLisle Mandy
Richard Steven Horvitz Billy
Greg Eagles Grim