Leprechaun

A leprechaun is a NetHack monster whose main "attack" is to steal some of your gold and teleport away. This makes them, primarily, annoyances. Leprechauns are best attacked with ranged weapons or spells. Eating a leprechaun's corpse has a chance of conveying teleportitis.

Leprechaun halls exist in the NetHack dungeon; these are special rooms filled with many, many leprechauns as well as gold.