ghoulia is probably my favorite g3 monster high character! in g1, she ties for me with venus mcflytrap, who i favored a bit more as a kid destined to become a punk anarcho-dyke.
ghoulia, in canon, is a zombie with limited mobility & who doesn't speak english, instead speaking in "zombie," AKA grunting and moaning, which her friends learn for her.
in my mind and heart, she's a nonverbal cripple punk & autist who communicates through nonverbal speech and gestures, with a game & comics special interest.
ghoulia's special interest varies across generations! in generation 1, she's a massive comic book enthusiast, and specifically a superfan of the comic franchise dead fast! the story surrounds a zombie who gains super speed and fights to protect other zombies, who are often discriminated against.
she also loves skateboarding, which fulfills her need for speed--and her skateboard has dead fast himself painted on it!
(she also skateboards without a helmet, but i guess that's fair since she doesn't have a brain that needs protection.)