Last week I pulled what I call a “Sleeper Agent”. One of the party members was switched by a very powerful shape shifter. The PC had been knocked out and the rest of the party gave chase. They lost their quarry for a min, which was all the time I needed. The bad guys stripped the PC of gear and gave it to the shape shifter. I didn’t tell the players that though. I told the PC who had been knocked out that he woke up as the bad guys was carrying him. The PC wiggled free and the bad guy took off. This all happened in front of everyone. I could see a few other players looking at me funny. Gears were turning, but they blew it off.
Later in the game the PC/shape shifter started rolling poorly, but nothing bad ever happened to him. The bad guys never went after him and he succeeded at all he did. He was having a blast while the paladin just kept looking at him with questioning eyes. I could tell the paladin knew something was up, but he also knew that the player who’s PC had been switched wasn’t good at lying or playing it cool. It didn’t add up.
We get to the final fight of the evening. The high priest of an eeeeevil cult is getting ready to sacrifice the PC who had been switched. The PC was unconscious on the alter and wrapped from head to toe in some religious garb so the PCs didn’t know who it was. Fighting broke out. The sleeper agent took out most of the little cultists (which was part of the ritual) and the other two PCs took care of the big bads. The ritual came to a peak and with some quick thinking and a lucky roll the thief saved his friend on the alter. The ritual was stopped. The bad guys made a hasty retreat using a teleport spell. The sleeper agent moved to the bad guy’s side and went with them willingly. The party all looked at me with a WTF in their eyes. Then they checked on the sacrifice and found their friend. Everything clicked for them immediately.
The only thing I wished I had done differently was to have the sleeper agent start missing all of his attacks and “accidentally” hitting the other players. He had done everything perfectly regardless of rolls so it stands to reason it would have been fun (for me) to go the other way. Oh well. Over all, the group thought it was pretty awesome, and the player of the sleeper agent got to play his character even though he was tied up for the whole session.