|Illustration copyright Alex Babakitis - used with permission - http://babakitis.com/
Not actually a phantom and not even undead, the Temple Phantom is a malign creature from a parallel dimension.
Over time, the prayers of worshippers build a conduit between the mortal realm and the outer planes. This conduit is strengthened and reinforced by the act of worship, but if a temple falls into ruin or is abandoned, this path can become fragile and "other things" can slip in from the spaces between worlds.
The temple phantom is one of those things. Looking like a toothy mass with six grasping claws, the temple phantom slips into our world looking for living prey. Its body is used to significantly warmer temperatures, so it frequently wraps itself in whatever cloth it can find -- usually tapestries, burial wraps or other discarded fabric.
It is this flowing fabric, as the temple phantom flies through the air, that give it its misnomer.
The temple phantom cannot be turned by clerics. It has an impeccable sense of smell and can track prey at great distances. Temple phantoms are immune to non magical weapons, sleep, charm, hold and poison.
Being an entity from "elsewhere," the temple phantom is strongly attracted to magic. It prefers to attack magic users over other victims. If more than one magic user is present, add up all the levels of their currently memorized spells. It will attack the magic user with the higher total. If no magic user is present, it will attack a cleric. If no cleric, it will attack at random.
When a target has been located, it swoops in attacking with all of its claws. If three or more claws hit, it will grasp its prey and automatically bite for d8 damage (no roll to hit necessary.) Each subsequent turn it will automatically bite for d8 and crush/claw/squeeze for an additional 2d4. Grabbed victims cannot cast spells.
If the bitten victim is a magic user, she must save vs. magic or lose 1d4 levels of memorized spells, randomly determined by the GM.
Grabbed victims must make two successful STR checks (1 per round for 2 rounds) to escape. Killing the temple phantom will cause it to dissolve into nothingness releasing the victim.