Ass-born NPC

ass-born NPC, n.: an NPC created by a GM out of thin air, usu. in response to an unforeseen player action; often said NPC has no stats or other character information, or such information also has to be invented on the spot; from "I pulled an NPC out of my ass."
Ex: Player: "I walk into the tavern." GM: "Um, oh, okay, well, there's an orc bartender behind the bar." Player: "An orc? I pull my broadsword and attack!" GM: "What? He's not a real monster! I pulled him out of my ass!" See also phantom ghoul. [GJ1]