BEHOLDER

The beholder (eye tyrant, sphere of many eyes) is most frequently found underground, although it infrequently will lair in desolate wildernesses. The beholder is hateful, aggressive, and avaricious. They will usually attack immediately. If confronted by a particularly powerful party there is a 50% chance they will listen to negotiations — either to be bribed not to attack or to pay a ransom to not be attacked, depending on the strength of the opposing party.

The globular body of this monster is supported by levitation, and it floats slowly about as it wills.

Atop the sphere are 10 eyestalks, while in its central area are a great eleventh eye and a large mouth filled with pointed teeth. The body is protected by a hard chitinous covering.

The creature's eyestalks and eyes are also protected, although less well (thus the armor classes of 2 and 7 respectively). 

The various eyes of a beholder each have a different function.

Typically only the central eye, plus 1-4 of those on stalks are able to function considering that the attack is coming from an are 90° before the monster. If attacks come from 180° double the number of eyestalks able to function, and for 270° or 360° triple or quadruple the number. Attacks from above enable all 10 eyestalks to function, but the central eye cannot.

Functions of the eyes are:

They can speak their own language as well as that tongue known to Lawful Evil creatures.

It is possible that this monster is a relative of the beholder, for there are remarkable similarities between the two species. The eye of the deep dwells only at great depths of the ocean, floating slowly about, stalking prey. The eye of the deep is hateful and aggressive, generally conforming to its land-dwelling cousin, the beholder, as regards temperament.

It has two huge crab-like pincers to seize its victims and a mouth full of small sharp teeth. Its primary weapons, however, are its eyes.

The creature has a large central eye which emits a blinding flash of light to dazzle and stun those in its ray (cone ½" at eye extending 3" to a 2" diameter base) for 2-8 melee rounds unless a saving throw versus death ray/Poison is made.

The eye of the deep also has two smaller eyes on long stalks with which it is able to create an illusion; or, acting independently, the small eyes are able to cast hold person and hold monster spells respectively.

Because it inhabits the deeps, this monster has an armor class of 5 everywhere, including eyes and eye stalks. It can withstand 10 to 12 dice of damage before being killed. If its eyestalks are severed they will, as with those of a beholder, grow back in about a week of time.