The entirety of "Wild Parts" is nauseating, with multiple scenes where characters pick their noses or eat food contaminated with mucus, but the ending takes the cake. After the antagonist's nose explodes (covering the entire screen in snot in the process), Billy uses a knife to cut his own in half so he can share it with the Nose Wizard.
"Hog Wild":
There's a long, graphic scene where an alligator triggers his own gag reflex to vomit Billy.
When the episode ends, the closing iris closes on Billy's head, causing a bunch of veins and snot to come out from his nose and one of his eyes to pop out.
The premise of "He Is Not Dead, He is My Mascot" is that Billy forces Grim to resurrect the school mascot cat as an undead. That, in itself, is pretty bad, but when Billy asks the zombie cat to scratch his back, his skin and muscle get shredded by the cat's splintered claws, causing his spinal column to poke out.
"Zip Your Fly": Mandy accidentally swaps her head with that of a fly after messing with Grim's zipper. That's pretty standard for the show, but then after losing the zipper to the dump, she ends up eating the entire landfill before she can find it and get her body back.
"Reap Walking": Harold eating a living, mucus-covered rat and slurping its tail as if it was spaghetti is probably the most disgusting scene on the show. Even the other characters, including Billy, react to this moment with utter repulse.
"The Loser from the Earth's Core": The close-up of Billy's frostbit hands, followed by one of his fingers falling off.
"Herbicidal Maniac": Skarr disguises himself as a bush so he can stalk Billy. Unfortunately, Jeff mistakes the general for an actual plant and decides that's an ideal place to hide his offspring. What follows is a 30-second long scene with Jeff graphically ejecting slimy purple eggs from his rear end into Skarr.
"The Bubble With Billy": Billy swallows a magic gumball machine, which causes him to projectile vomit uncontrollably until most of the Earth is covered in sticky gum. After he is done, he suffers a sudden allergic reaction, causing his face to be covered in blisters and boils.
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