Gel-arshie
From Homestar Runner Wiki
Gel-arshie is the equally alarming mascot for Red Flavored Fluffy Puff Translucent Dessert Related Substance, and was only featured in winter pool. He appears to be made of red gelatin dessert, and seems to have a brain floating in the center. May be Marshie in disguise, or may be his eerie "abomination" of a cousin. Strong Bad also thinks the commercial should be rated NC-17 (for 'Needlessly Creepy times 17').
Complete Filmography
Debut: winter pool