Anarexic Dinosaur

Hey, listen up, genius! So, like, there's this big lizard, a dinosaur, right? But it's super skinny 'cause it can't eat. What do you call it? An "Anarexic" – get it? It sounds like "anorexic," which is when someone doesn't eat. You probably don't know what food is. The joke is funny because it's a play on words.