The following material is Open Game Content from the Menace Manual SRD
WHISPERER IN THE DARK
From a distance, a whisperer in the dark resembles a swirling bank of mist or light fog, but an observer within 30 feet of the whisperer can clearly see dozens of humanoid faces in the fog, silently screaming their endless torment.
Daylight Powerlessness (Ex): A whisperer in the dark is utterly powerless in natural sunlight and flees from it if possible. If caught in sunlight, it cannot attack and may make only one move or attack action each round. It cannot take full-round actions at all in this situation.
Incorporeal Subtype (Su): A whisperer in the dark has no physical form and can be harmed only by other incorporeal creatures, +1 or better magic weapons, or magic, though it has a 50% chance to ignore any damage from a corporeal source. The whisperer in the dark can pass through solid objects at will, and its own attacks pass through armor. The charred one moves in complete silence and cannot be heard at all.
Psionics (Sp): At will—attraction, clairaudience/clairvoyance, concussion, detect psionics, suggestion. Manifester level 10th; save DC 10 + whisperer in the dark’s key ability modifier + power level.
Steal Essence (Su): If a creature with an Intelligence score greater than 2 is slain by a whisperer in the dark, its essence is absorbed into the monster’s consciousness within 1d4 rounds, though its physical body remains intact. Stealing a creature’s essence grants the whisperer 12 temporary hit points, and a new screaming face resembling that of the absorbed creature appears permanently within the cloud.
Turn Resistance +2 (Su): A whisperer in the dark is treated as having +2 Hit Dice for the purpose of turn or rebuke attempts.
Undead: A whisperer in the dark has the traits and immunities common to undead.
Unnatural Aura (Su): A whisperer in the dark constantly projects an unnatural aura to a radius of 30 feet around itself. Both wild and domesticated animals can sense this aura and refuse to enter its area. If forced to come closer than 30 feet to the whisperer in the dark, they panic and remain panicked for as long as they are in the area.
Whisperer in the Dark: CR 12; Large undead (incorporeal); HD 11d12; hp 71; Mas —; Init +7; Spd 30 ft., fly 60 ft. (good); Defense 14, touch 14, flat-footed 11 (–1 size, +3 Dex, +2 deflection); BAB +5; Grap —; Atk +4 melee (2d6 Con, incorporeal touch); Full Atk +4 melee (2d6 Con, 4 incorporeal touches); FS 5 ft. by 5 ft.; Reach 10 ft.; SQ daylight powerlessness, incorporeal, psionics, steal essence, turn resistance +2, undead, unnatural aura; AL chaos, evil; SV Fort +3, Ref +6, Will +9; AP 0; Rep +0; Str —, Dex 16, Con —, Int 14, Wis 14, Cha 15.
Skills: Concentration +8, Hide +13, Intimidate +12, Listen +12, Search +12, Sense Motive +8, Spot +12.
Feats: Alertness, Blind-Fight, Combat Reflexes, Frightful Presence, Improved Initiative.
Advancement: 12–18 HD (Huge); 19–26 HD (Gargantuan).