Skeleton Ship, Hell's Cruiser

Islandwalk
If you control no islands, sacrifice Skeleton Ship, Hell's Cruiser.
{t}: Put X -1/-1 counters on target creature,
where X is Skeleton Ship, Hell's Cruiser's toughness.
{t}: Put a +1/+1 counter on Skeleton Ship, Hell's Cruiser.
Whenever a creature with a -1/-1 counter dies, scry 1.