Oh crap here comes another. >)
Mwanga is from Nyambe: African Adventures, Alien Entity is from Legends and Lairs: Monster's Handbook, Pseudonatural is from Tome and Blood, Psionic is from Psionicist's handbook.
Void Viper (Medusa + Mwanga + Alien Entity + Pseudonatural + Psionic)
Medium Aberration
Hit Dice: 6d8+30 (57)
Initiative: +11 (+7 Dex +4 Improved Initiative)
Speed: 30 Ft, 60 Ft. Fly (Average)
AC: 24 (+7 Dex, +7 Natural)
Attacks: Shortbow +8/+3 ranged; or dagger +8/+3 melee, snakes +3 melee, bite +3 melee
Damage: Shortbow 1d6; or dagger 1d4+5, snakes 1d4+3 and poison, bite 1d4+3 and poison
Face/Reach: 5 Ft. By 5ft/5ft
Special Attacks: Petrifying gaze, poison, Psionics
Special Qualities: Damage Reduction 15/+1, Spell Immunities, SR: 16,
Electricity and Acid resistance 10, Telepathy
Saves: Fort: +5 Ref: +14 Will: +5
Abilities: Str:16, Dex:25, Con:20, Int:4, Wis:7, Cha:11
Skills: Bluff +8, Disguise +4, Hide +11, Intimidate +4, Move Silently +11,
Sense Motive +2, Spot +8
Feats: Point Blank Shot, Precise Shot, Weapon Finesse (snakes), Alertness. Dodge, Improved Initiative, Lightning Reflexes, Concentrated Venom#, Iron Will
Climate/Terrain: Any land and underground
Organization: Solitary, pair, or gang (2-5)
Challenge Rating: 13
Treasure: Standard
Alignment: Always Chaotic Evil
Advancement: By character class
# = From Legends and Lairs: Monster’s Handbook
Void Vipers are strange creatures, thought to be the beings that created the Medusae on the Prime. However, the truth is enough to shatter minds. Most beings have been fortunate enough to never run across the realm the Void Vipers call home. A place beyond the regular spectrum of planes.
In their “natural” form Void Vipers stand at 7 feet tall. They are extremely gaunt, their skin is translucent and bizarre alien organs can be seen beneath. They have no wings yet manage to fly. They are vaguely humanoid, they have no faces, and the snakes like appendages on their heads are like stingers. They use their telepathic power to speak when needed, they rarely do. However, the Void Viper has a plethora of shapes it can take including that of a regular medusa, dire rat, dire bat, and a leopard.
They feed on blood.
Combat
The Void Viper can switch from Petrification to Charm gazes as a free action. They usually soften an opponent up with psionic attacks while in the form of a leopard, bat, or rat. Once this is accomplished the Void Viper takes its true form and drains the victim dry.
Alternate Form (Su): A Void Viper can assume the shape of leopard, dire rat, or dire bat as a standard action. This ability is similar to a polymorph self spell cast by a 12th level sorcerer, except that the Void Viper can assume only one of the forms listed here. It can remain in that form until it assumes another, or until the next sunrise.
In addition, at will a Void Viper can take its true shape. Changing shape is a standard action. Other creatures receive a –1 morale penalty against the Void Viper in its true form.
Blood Drain (Su): A Void Viper can suck blood from a living victim with its fangs by making a successful grapple check. If it pins the foe, it drains the blood, inflicting 1d4 points of permanent Constitution drain each round the pin is maintained. The Void Viper gains 5 temporary hit points. These vanish at the rate of one per hour.
Charm Gaze (Su): A Void Viper has a gaze attack that functions as a charm person spell cast by a 12th-level sorcerer. This has a range of 30.
Create Spawn (Su): A humanoid or monstrous humanoid whose constitution is drained to 0 or less Constitution by the Blood Drain attack dies. A humanoid or monstrous humanoid of 5 or more HD is transformed into a Mwanga and regains drained Constitution points at a rate of 1 per day. The new mwanga is under the command of the Void Viper that created it and remains enslaved until its master’s death.
Improved Grab (Ex): To use this ability, the Void Viper must hit with its bite attack. If it gets a hold, it can drain blood.
Petrifying Gaze (Su): Turn to stone permanently, 30 feet, Fortitude save (DC 15).
Psionics (Sp): At will - Planeshift, Shadow Body, and Mind Seed. These abilities are as the powers manifested by an 6th-level psion.
Attack/Defense Modes (Sp): At will – ego whip, id insinuation/empty mind, mental barrier
Poison (Ex): Snakes, Foritude save (DC 14); initial damage 1d6 temporary Strength, secondary damage 2d6 temporary Strength.
Regeneration (Ex): Cold and Electricity deal normal damage to a Void Viper.
If a Void Viper loses a limb or body part, the lost portion regrows in 3d6 minutes. The creature can reattach the severed member instantly by holding it to the stump.
Spell Immunity: A Void Viper is immune to all mind-influencing effects and spells from the Enchantment school.
Telepathy (Su): A Void Viper creature can communicate telepathically with any creature witin 100 feet that has a language.
True Strike (Su): Once per day, the creature can make a normal attack with a +20 insight modifier on a single attack roll. The creature is not affected by the chance that apples to attacks against a concealed target.
Skills
Void Vipers recieve a +4 racial bonus to Bluff, Intimidate, Hide, Move Silently, and Sense Motive.