You take the kinfe that's being handed to you and approach the goat. It's tied down and immobile, so your job is easy. You raise the knife high above your head, then plunge it into the goat. The violence feels good, better than you could have anticipated, and you plunge the knife into the animal again and again. Then, as you're standing there amid the gore, something starts to rise from within the goat. It's dark and terrible, made of blood and fire. And it sings:
"Now that you've unleashed me, "I release my demons three "To sow the seeds of anarchy "and bring the end of all things."
You don't see these other three demons, but apparently he wasn't bluffing; the party wraps up after that and you head back home, only to find the apocalypse well under way. There are pillars of flames and gaping chasms where your neighbors used to live. The streets run with blood. When you awake, it's with a sense that you've somehow failed this whole plane of existence.