So, in our most recent session, my party was fighting a ghost. In the confusion, the ghost managed to use its malevolence ability on a PC isolated from the rest of the group. The DM was pretty clever, and the ghost managed to pass as a member of the party until the fight with the other mooks had finished. At the end, our paladin let off a channel to heal us all back up. This raised an interesting question, since the Magic Jar description and the malevolence description don't really clarify. The ghost is still an undead, so does the channel of positive energy still affect it as undead? Or does being in the body protect it?
Ah, good point. I've not played a cleric or paladin and completely forgot you have to choose when using channel. If, in a similar situation, though, the cleric did choose to turn instead of heal, could you damage the undead?
I would say yes. It's still undead - and therefore affected.