Foretell The Tide

Foretell {3}{u}{u} (During your turn, you may pay {2} and exile this card from your hand face down.
Cast it on a later turn for its foretell cost.)
Create X 1/1 blue merfolk tokens, where X is the number of copies of this spell foretold this game
plus 1. If X was seven or more, return all non-
merfolk permanents into their owner's hands.