Parasitize

Crystallize {w}{w}{w}(When you successfully cast this
spell from your hand, exile it and create a Crystal
artifact token with "{w}{w}{w}, Sacrifice this permanent:
You may cast Parasitize from exile for {0} until end
of turn.")
Destroy target nonartifact creature that's
attacking. If Parasitize was cast from exile, target
player gains life equal to its toughness.