The Beholders are magical floating, eye-covered, tentacled beasts. They can teleport enemies (usually Ruborians) into combat, and by the same token can teleport away any minions that go directly beneath them, presumably to be killed. There is a fiery variant that is immune to fire attacks and summons Ruborian Bombers.
They are very dangerous for the Overlord and his minions. Luckily they have one weakness, they can be attacked from above with Reds or Greens.
Fellowship of Evil Edit
The Beholders make a return in Fellowship of Evil, but are here, called Void Gazers. These creatures are visible in Hollowmurk where Nether Elves invoke them through human the Shining Justice deliver them.
They are very similar to Beholders of the Dungeons and Dragons Universe.
They also look similar to Overseers from Starcraft 2.