Erymis, Queen of the Undine

Islandwalk
When Erymis, Queen of the Undine enters the battlefield, each land becomes an island in addition to it's other types.
Whenever Erymis, Queen of the Undine deals combat damage to a player, that player puts the top X cards of his or her library into his or her graveyard, where X is the number of islands on the battlefield.