Crabviathan

Whenever Crabviathan attacks, sacrifice it unless you sacrifice two islands. If you choose to sacrifice islands, put them under Crabviathan.
When Crabviathan dies, put all islands under Crabviathan on the battlefield tapped.
"This monster has been terrorising the seas for awhile now. But actually, it's just really hungry. So we give it some islands to feed that we make more of after that." - Ying, Goddess of Life and Nature