1. A demon that emerges out of your asshole if you have anal sex.
2. A particularly nasty shit.
3. A backdoor pirate...AKA person who likes to stick their god given meat inside of other people's assholes.
Pope: "If you have anal sex the butt demon will crucify you on your toilet."
Zach: "I just left a godly butt demon in the toilet."
Rodion: "Joey is a butt demon."
Tyler: "So is Brutis."
A giant shit that you almost can't get out. It's like giving birth through your asshole. Usually it tears the anal ring and you bleed. And sometimes the demon can infect the wound. The only way to prevent these demons from occurring is through anal exercises.
"RELEASE THE BUTT DEMONS!!!!!!!!!!!!!!!!!"