Sorcery, 5WW (7) Remove all permanents from the game. As long as any of those cards remain removed from the game, at the beginning of each player's upkeep, that player returns one of the removed cards he or she owns to play.
Illus. Dave Dorman
Each player chooses which one of cards which was removed by this specific effect to return during each of their upkeeps. [Scourge FAQ 2003/05/30]
Remember that the returned creature just came under your control, so it cannot attack until you start a turn with it under your control. [Scourge FAQ 2003/05/30]
You cannot pick a card that cannot legally be returned to play (see Rule 413.2c). If there are no cards that can be legally returned, then you cannot pick one. [D'Angelo 2003/09/08]