Whirlpool Devourer

You may return 4 Islands you control to your
hand rather than pay the mana cost of Whirlpool Devourer.

Pulled Under —When Whirlpool Devourer deals combat damage to an opposing creature, exile that creature until Whirlpool Devourer leaves play. Whirpool Devourer can block up to X attacking creatures, where X is the number of Islands you control rounded down. Creatures that are exiled with Whirlpool Devourer return to the bottom of their owner's library in a random order when he leaves play