Slang for Anorexia Nervosia. Used mainly as an insult for friends who believe they are fat and opt to not buy/eat food.
"Thomas, what are you ordering?"
"Meh. I think I'll get a cruton"
"WTF mate? A cruton? what are you a fatass?"
"Don't call me fat!"
"You are fat you A-rex son of a biotch"