Mighty Megalodon

{t}: Mighty Megalodon submerges. Activate
only as a sorcery. (This creature phases out.
On the turn it phases in, it can't be blocked.)
Whenever Mighty Megalodon surfaces, you
may sacrifice a creature. If you do, Mighty
Megalodon gets +3/+0 until end of turn.
Blood in the water means feeding time.