Ginungar, Husher of Vessels

Ginungar cannot attack or block.
When Ginungar enters the battlefield, it senses
the presence of nearby captains who were foolish enough to sail the dreaded waters where it resides.
If there are no captains present, Ginungar
slumbers...
Whenever a Captain or Ship performs any action,
put a Deathmark counter on them. Then, flip a
coin for each counter. If any of them are tails, Ginungar devours that permanent.