Pact of Mutation

Pact of Mutation is green and blue.
You may sacrifice a creature. If you do, search
your library for a creature card with converted
mana cost equal to 1 plus that creature's
converted mana cost, put that card onto the battlefield, then shuffle your library.
At the beginning of your next upkeep, pay {2}{g}{u}. If you don't, you lose the game.