The beholder, or “eye tyrant”, is one of the most iconic of D&D monsters. They are vicious and cruel creatures, covetous of wealth and power. They believe themselves to be perfect beings, the pinnacles of evolution, and treat all “lower” beings with disdain, mere disposable resources to be expended in the pursuit of their vicious ambitions. They are wary and distrustful even of other beholders. Still more pathologically, their own minds are divided into two halves, each of which distrusts the other, and so they hoard secrets within and from themselves. They float through dungeons of their own making, alien and alienated, smug, abominable, and terribly, terribly alone.
Y’know, just like us.
We sure do like monsters that are secretly self-portraits.