Yemoja, the Sea-Shaper

Yemoja, the Sea-Shaper costs {1} less to play for
each non-Island land your opponents control.
Trample, hexproof
Yemoja, the Sea-Shaper can't attack unless
defending player controls a non-Island land.
Whenever Yemoja, the Sea-Shaper deals combat
damage to a player, up to that many lands that
player controls become basic Islands.