Creast

(Noun/Insult) Moldy milk has been left for 20+ minutes. If you do this you're an idiot. Or someone who has a crusty personality.

Mom: Didn't I tell you to finish your milk? Now look, Some creast!
Me: You are creast.

Creast

Crusty flakes that have been left for 20+ minutes. If you do this you either have a bad memory or you're an idiot.

Mom: Didn't I tell you to put the flakes back? Now look at this, some creast!
Me: You are creast.