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 that card 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. That spell costs {2} less to cast. If that
spell would be put into your graveyard, exile it instead.