| SlimGauge |
I assume you mean the Possession spell. I further assume Daw means "Never Mind" by "NM", I suspect he began a reply, changed his mind, altered it to NM, but I don't claim to know for sure.
Unlike Dominate Person, Possession does NOT say "a Sense Motive check against DC 15 (rather than DC 25) can determine that the subject's behavior is being influenced by an enchantment effect".
The Sense Motive skill has this use
"Sense Enchantment: You can tell that someone's behavior is being influenced by an enchantment effect even if that person isn't aware of it. The usual DC is 25, but if the target is dominated (see dominate person), the DC is only 15 because of the limited range of the target's activities."
Possession is not an enchantment effect, it is of the necromancy school. Thus, this use doesn't technically apply. As a GM, I might allow it with a higher DC.
Interestingly (at least to me), Detect Thoughts looks like it would work if concentrated on for two rounds.
| Claxon |
Presumably when you interact with the creature it doesn't necessarily know how the creature it's possessing would regularly behave, you should get sense motive checks to notice something isn't right with your friend.
The possessor probably needs ranks in perform/bluff to act the part of the possessed individual which would be opposed by sense motive.
| SodiumTelluride |
Here's how I handled it in our home game. I recognize that this only works in a group that knows each other and is willing to roleplay, but it worked pretty well for us.
The enemy cast magic jar (which works the same as possession for purposes of this question). I chose the target, but had everyone make Will saves. Fortunately for me, my chosen target failed his. Then I took each person out of the room individually. To most of them I simply said "Nothing happens. But stay here for a second, to make it look like I'm telling you something special." To my target, I explained what had happened and asked him to play as someone who knows little of the adventure so far, and virtually nothing of the other PC's, but is doing his best to not attract attention to himself. Then when we resumed play, I simply let the chips fall where they may-- the group did figure out who it was after not very long, but it made it more fun than simply rolling to beat a DC.