Thassa's Devourer

You have hexproof. (You can't be the target of spells or abilities your opponents control.)

2W, Sacrifice this enchantment: You gain 7 life.

Counter target spell. Its controller mills four cards.

Constellation — Whenever this creature or another enchantment you control enters, you gain 1 life. WB, Pay 1 life: Each opponent loses 1 life.

Whenever this creature attacks, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Vigilance 6G: Monstrosity 3. (If this creature isn't monstrous, put three +1/+1 counters on it and it becomes monstrous.)

Squelching Leeches's power and toughness are each equal to the number of Swamps you control.