In the name of Urgathoa: RAISE!
For some reason, it can't be found at the Archives anymore, and D20PfSRD doesn't have it either. Maybe because it's a 3.5 feat. However, you can find it in the book or here:
Pathfinder community feat list (entry 2627, pretty much at the bottom; table needs a while to load)
For convenience, here are the requirements and the start of the lenghty text:
Possess Creature
A fiend gains the ability to merge its physical form with another creature’s body, spreading its foul influence from within a living vessel.
Prerequisites: Cha 20, any evil outsider with 10 or more Hit Dice.
Benefit: Once per day, as a full-round action, a fiend can discorporate into a malign presence and target a creature within 15 feet. The creature targeted must succeed at a Will save equal to 10 + half the fiend’s Hit Dice + the fiend’s Charisma modifier or be possessed (see below). Targets under the effects of protection from evil, or related spells, gain a bonus to this save. Should a target succeed at its Will save, the fiend is forced back into its natural form and is stunned for 1 round.
A fiend that successfully possesses a target enters its space and merges with it. (...)
Would you allow it for evil tieflings - or more general, for all evil native outsiders?