Fetid-works
Land-Island Swamp (Rare)

(Tap: Add U or B to your mana pool.)

When Fetid-works enters the battlefield, you lose 1 life unless you reveal an artifact creature card from your hand.

BB, Tap, Sacrifice Fetid-works: Put a -1/-1 counter on target creature.

2, Tap: Target land becomes a 3/3 blue Merfolk Fish creature until end of turn. It's still a land.

Rebecca Pollack