Death tyrant

Death tyrants were an undead form of beholder, similar to zombies, that retained some innate magical abilities. They were often used by powerful wizards as guardians. They were almost never encountered near other beholders, who found them abhorrent.

Description
A death tyrant was the result of a beholder's mad dreams of existing beyond death. On the rare occasion in which such dreams took hold of a live beholder, its flesh rotted away, and a naked skull with spectral points of red light for eyes would emerge. A death tyrant held much of the powers of the original beholder, now fueled by the power of Undeath.

Although somewhat similar to a zombie, a death tyrant was a much more powerful creature, that continued to lord over others the same way beholders did. On the other hand, a true beholder zombie was the result of the necromantic reanimation of a dead beholder, and although a formidable foe, was a considerably weaker creature and a mindless servant.