KMS U-96

Submerge (This creature can't be blocked except by
creatures with submerge.)

Whenever KMS U-96 attacks, look at the top card
of your library. You may put it into your graveyard.
Whenever KMS U-96 deals combat damage to a player, you may cast an instant or sorcery spell from your graveyard this turn. If that spell would be put into your graveyard, exile it instead.