The moai is a recurring character in Mark Lilly's class. He first appears in the episode "An American Werewolf in America" attending Mark's funeral (and resurrection). He often wears a green tank and blue shorts.
He seldoms speak but on his first appearance in the class in "Demon Baby", he comments on Mark's young age as Mark talks about parenting.
He has a son, as seen in the opening sequence in "Kong of Queens".