When Icy Prison enters the battlefield, exile target creature.
At the beginning of your upkeep, sacrifice Icy Prison unless any player pays.
When Icy Prison leaves the battlefield, return the exiled card to the battlefield under its owner's control.
10/1/2008 If Icy Prison leaves the battlefield before its first ability has resolved, its third ability will trigger and do nothing. Then its first ability will resolve and exile the targeted creature forever.