Whirlpool Stalker

Whenever Whirlpool Stalker attacks, you
may tap or untap target permanent.
As long as Whirlpool Stalker is untapped, whenever a creature blocks it, that creature
gets -2/-0 until end of turn.
When the tide's not on your side, and your world begins to spin, that's the time to close your eyes, say your prayers, give in.