In Dominion: Alchemy, you can play Possession to "possess" the player to your left and effectively take over his next turn. What happens if he has a Possession in his hand, and you play it during that possessed turn?
(Turn order is Alex, then Bob, then Carl)
Alex plays Possession.
He controls Bob's next turn, and plays a Possession from Bob's hand.
This means someone will possess Carl on the next turn - but is it Bob, or Alex?