Yet Another Funny Message (YAFM) is any (often unintentionally) funny message you might receive during the game. For example, if you are blind and drop an object just before a yellow light attacks you, you might get some interesting results: You drop an uncursed cockatrice corpse. It explodes! Intentional funny messages may be received for example in rare battles that the player might see: The fire elemental hits the water elemental. The water elemental is boiling! The origin of all of these terms is probably rec.games.roguelike.nethack.