An Oculus Somno, sometimes called a Morpheon, appears as a slate-colored, slightly lumpy sphere with a single large eye. It has no mouth, but rather has three jointed probosci arranged around its lower hemisphere; they fold up tight against the body when not in use and may thus be overlooked. The carapace of this monster is tough and resilient, and they are the swiftest fliers of all oculus species.

The main power of an oculus somno is its ability to put its victims to sleep. Anyone who meets the gaze of one must save vs. Paralysis or be put to sleep (as the spell, but with no limit as to hit dice or levels that can be affected). An oculus somno will use its probosci only if it succeeds in either placing all members of a party into a state of sleep or driving them away. When it faces no opposition, the monster will move into a position where it can reach the maximum number of victims at the same time, and then pierce each one with a proboscis (this will not awaken a sleeping victim) and begin draining the victim’s blood.

For each 1d6 damage roll, the monster recovers one lost hit point (if any). Its appetite is not limited to these lost hit points, however, and it can and will drain dry more than a dozen man-sized victims.

Oculus somni communicate with each other, and infrequently with other oculi, using an inherent telepathic ability; while it is possible for the monster to communicate with other species in this way, they rarely if ever choose to do so.