Beholder

Beholders are powerful aberrations that originate in the Far Realm.

Description
A beholder's body consists of a hovering head with a wide and toothy maw, an enormous central eye, and ten independently moving eyes at the end of their own eyestalks.

Abilities

 * Immunities: The "prone" condition.
 * Senses: Darkvision.
 * Languages: Deep Speech, Undercommon.
 * Attacks
 * Antimagic Cone: The beholder can negate magic within a 150-ft cone in front of its central eye.
 * Also negates the effects of its own eye rays within that area.
 * Bite: The beholder can bite at a target with its giant, toothy maw.
 * Eye Rays: A beholder has ten different eyes attached to its head, each of which can emit a different magical ray at separately selected targets.
 * Legendary Action: A beholder can use one of its eye rays at the end of another character's turn.

Known beholders

 * K'Varn, bearing a Horn of Orcus and metal armor plating, came through a rift from the Far Realm to the ancient underground city of Yug'Voril, where he enslaved a mind flayer colony, expanded his influence to the duergar Emberhold, and began threatening Kraghammer before he was slain by Vox Machina.
 * A beholder—possibly named something pronounced "Yar-voss," based on what its kuo-toa servant said as it died—occupied the sunken tomb of Purvan Suul.
 * Enxanash is an eccentric beholder living in a hidden valley in the Cyrios Mountains.
 * Taryon Darrington claimed to have killed a small beholder at some point in the past with help from sellswords, who "took it out into a field and sort of roughed it up" for Taryon, who then dealt the killing blow to the creature.

Trivia

 * Due to beholders being Product Identity of Wizards of the Coast under the Open Game License, they are replaced with unspecified extra-planar aberrations in the Critical Role: Tal'Dorei Campaign Setting. One adventure hook involves aberrant "Death Eyes", which sound similar to a nickname for despotic beholders, "eye tyrants", and an undead type of beholder called a "death tyrant".
 * In The Legend of Vox Machina, the beholder in Purvan Suul's tomb is replaced with a similar creature called an "onlooker". The onlooker has tentacles instead of eye stalks, which burrow into the ground and petrify the creatures that it touches.