Skeletal Vents
Land-Island Swamp (Rare)

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

Whenever Skeletal Vents becomes tapped, it deals 1 damage to you.

BB, Tap, Sacrifice Skeletal Vents: Put a -1/-1 counter on target creature.

2U, Tap: Put a 1/1 blue Shapeshifter creature token with flying onto the battlefield.

Eric Moeller