Debris Mire
Land (Rare)

Debris Mire enters the battlefield tapped.

Tap: Add U or B to your mana pool.

Tap: Add 2 to your mana pool. Put Debris Mire on top of your library.

2: Debris Mire becomes a 2/2 blue Merfolk creature until end of turn. It's still a land.

Greg Myrfors