Black Loper (CR 2)

Medium Outsider
Alignment: Neutral evil
Initiative: +0; Senses: scent and Listen +7

AC: 19 (+4 Dex, +5 natural), touch 14, flat-footed 15
Hit Dice: 4d8+4 (25 hp); DR: 5/magic
Fort +5, Ref +4, Will +4
Speed: Fly 40 ft. (perfect)
Space: 10 ft./5 ft.
Base Attack +4; Grapple -1
Attack: Bite +10 melee; tentacle +7 melee
Full Attack: Bite +10 melee; tentacle +7 melee
Damage: Bite 2d6; tentacle 1d8 + acid
Special Attacks/Actions: Steal
Abilities: Str 15, Dex 18, Con 12, Int 5, Wis 17, Cha 10
Special Qualities: SR 10, cannot be flanked
Feats: Multiattack
Skills: Hide +7, Listen +7, Survival +7, and Tracking +4
Advancement: 3-4 HD (Medium-size); 5-7 HD (Large)
Climate/Terrain: Any
Organization: Solitary
Treasure/Possessions: None

Source: Web

Transfer: When it kills a victim, a black loper assumes the personality and fragments of memory of its victim. If it kills an intelligent person, then it wanders lost and aimless as it tries to somehow reconstruct its life, but remains basically unaware that it's the monster it truly has become. During a full moon, the creature's memories are lost and it reverts to its natural state, hunting as necessary to survive. Black lopers do not reproduce. They come from some other plane, but which plane and their method of entering the plane is unknown.