Sulfurous Park
Land-Swamp Forest (Rare)

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

Sulfurous Park enters the battlefield tapped unless you control one or more artifact creatures.

BB, Tap, Sacrifice Sulfurous Park: Put a -1/-1 counter on target creature.

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

Aleksi Critchlow