DRELB

Drelb inhabit the Negative Material Plane, but evil-minded persons will sometimes call them to the Prime Material Plane to serve as guardians of hidden wealth or secret places, so whenever they are encountered on this plane they are guarding something. 

Unfortunately a drelb looks so much like a wraith that one is indistinguishable from the other until an attack takes place. Magic which draws a drelb to the Prime Material Plane is likely to function only from sunset to sunrise; so, much like undead, drelb appear only in twilight or darkness.

The effect of the nether chill of a drelb is to make its victim fall shivering to the ground for the following round (no saving throw), immediately dropping anything it holds and unable to perform any actions until after the chill passes. 

When confronted by a cleric attempting to turn it, or if prey is hesitant, the cunning monster uses a trick of illusion. It causes its form to rapidly diminish in size while gliding smoothly forward. This is 90% likely to give the viewers) the impression that the drelb is retreating, while it is actually moving up to attack. Although drelb resemble undead, they are not and cannot be turned.

Magic weapons are needed to harm drelb; silver has no effect, unless it is magicked silver, which causes double damage.

Drelb also have the facility of imitation and/or reflection of psionic power. Any power used within 30 feet of the creature or any psionic attack directed at it is imitated or reflected back upon the attacker.

Drelb can speak only their own strange language, although they can understand simple phrases in the common tongue.