The Imposter

When The Imposter enters, you secretly choose a nontoken creature you don't control and this creature phases out. If The Imposter or the secretly chosen creature leaves the battlefield, reveal it.

Will of the council — At the beginning of your upkeep, starting with you, each player may vote for a nontoken creature you don’t control. Sacrifice each creature with the most votes, then sacrifice The Imposter. If the secretly chosen creature is on the battlefield, The Imposter phases out and you