Beholder, beholder, n., D&D-ism a monster from the original D&D; a large, globular floating body covered in thick plates, with a toothy slit-like mouth, and a single large eye; on top of the beholder's body is a ring of 10 smaller eyes on stalks; it has various magical powers such as Eye Blasts. [GJ1]
Addendum: The Beholder was one of the dumber monsters from D&D, like the Gelatinous Cube or the Gray Pudding. If you doubt that the Beholder is a stupid concept, you apparently didn't see the Dungeons & Dragons movie. [EDE]