Floating eyes, also known as beholders, are monstrous creatures found in Outland. Floating eyes are only seen in specific locations, and that is probably a good thing; many adventurers are struck with fear at the sight of such odd and malevolent beings. One of the bosses inside the Blood Furnace, a wing of Hellfire Citadel, is said to be such a being. Another beholder-type boss is found in the Auchenai Crypts instance. Other than that they are only found in Netherstorm and the Death's Door subzone of Blade's Edge Mountains, but it is also known that some were jailed in the Arcatraz, now free and roaming the ship due to the mischief of Kael'thas and his followers. Whatever created these abominations is still unknown.tBCOSG 321
They feature two rows of teeth and seven eyes. Floating eyes are demons in service to the Burning Legion, and appear to be intelligent. Interestingly, a number of eyes can be seen openly defying the Legion. Broggok and Shirrak the Dead Watcher are two examples of floating eyes that have gone rogue. This could imply that the eyes are less loyal to the Legion than other demonic species, or it could just be that Shirrak and Broggok are exceptions. Oddly, Shirrak is not actually classified as a demon, but is instead undead.
Eyes are the first demonic species that have been shown to have offspring. Young floating eyes possess only one eye, with far fewer teeth. They are also far less aggressive then their adult counterparts. You can obtain one of these offspring named Sleepy Willy during Children's Week.
They vaguely resemble (and get their name from) Beholders of Dungeons & Dragons fame, and are also similar in design to Cacodemons from Doom, as well as Octobrains from Duke Nukem 3D. A similiar name, Cacodaemons, is a race of daemon that exists in the Warcraft universe.
They have a sphincter on their backside that can be seen contracting when the creature is fighing and dilating when the creature dies. Its use is unknown.
Some eyes have been observed to speak. Their linguistic performance is at par with races like humans and orcs.
Their eyes can shoot rays of magic, like a laser. They are able to shoot several types of magic. It seems this ability is so powerful that the eyes can't help but sometimes fire at random with no reason, and continue to do so until they are drained of power and die.
Some eyes are also extremely poisonous. Many use acid-based attacks which either damage an opponent or the opponents armor. Sometimes when an eye dies, large amounts of poison will flow out from its body, making it lethal to even go near the corpse.
As a floating eye will fall to the ground when it falls asleep or dies, the levitation appears to require some sentience to be maintained rather than being a passive magical attribute.