Phase Transfer

The next time a nonland permanent enters the battlefield this turn it's controller sacrifices it, that player then reveals cards from the top of his or her library until a card is revealed that shares a converted mana cost with the sacrificed card, you may play that card without paying its mana cost and put the rest into your graveyard.
"The information stores of The Preservers....Purged...by Shardavan!? -Pontiff Toi