Tales of Tolgard
Turning is a special divine ability that every cleric has been granted by their deity. This allows them, when they have their holy symbol in hand, to have special interactions with undead. The possible results are based upon the alignment of their deity- this power is not given to true neutral deities, but only to those who operate on one extreme of the good evil axis.
Evil clerics can attempt to rebuke undead by channeling the negative energy of their patron deity. Sometimes this results in nothing happening at all, whether due to the fickleness of the deity in question, the lack of faith on the part of the cleric, or the extreme power of the undead in question. When undead are successfully rebuked they will cower in awe at the power of the cleric and the negative energy channeled through the cleric’s holy symbol.