Drowned Hydra

Islandwalk
Drowned Hydra enters the battlefield with X
+1/+1 counters on it.
Overpower - When Drowned hydra enters the battlefield, you may have it get +X/+0 where X is
its power, then have it fight any number of target creatures. If you do, sacrifice it at the beginning
of the next end step.
The sea is vast and full of terrors.