A small goblin-like animal with a Hitler mustache that resides inside a person's ass. At night, ass nazis leave their dwellings and venture outside to steal your underpants. See also: "Underpants Gnomes".
Person 1: "My ass itches."
Person 2: "Maybe you have ass nazis."
Person 1: "Yeah, I guess I'll have to eat some baked beans to flush 'em outta there."
The Art of Being an Ass Nazi is when someone is so up oneself's own ass, there is no fun to be had and Extermination of small races can be found. One that has been called ass nazi should be attacked in their sleep and a fake moustache be drawn on their face and when the person speaks, everone else must reply 'Heil Hitler'
Alan- Man Adam's Head is like 12 miles up his ass
Adam- Heil Hitler!
Alan- ass nazi