Wyatt: By the way, why are we wearing bras on our heads?
Gary: It's ceremonial.
[Later, after Wyatt talks to Chet, Wyatt begins to leave the kitchen and Chet sees him wearing women's underwear.]
Chet: Like your panties.
Wyatt: [walking back into kitchen] It's a joke, Chet. Really.
Chet: No. That is not a joke. That is a severe behavioral disorder. Next thing you know you'll be wearing a bra on your head.
Lisa: If you want to be a party animal, you have to learn to live in a jungle.
Lisa: I can be a real serious bitch if I don't get what I want.
Lisa: So, what would you little maniacs like to do first?
Answer: According to the Wikipedia page for this movie, Lisa transforms Chet into a giant, talking turd.
Casual Person