Mosswort Marsh
Land (Rare)

When Mosswort Marsh enters the battlefield, return a land you control to its owner's hand.

Tap: Add G to your mana pool. If you played a land this turn, Add B to your mana pool instead.

BG: Mosswort Marsh becomes a 2/1 green and black Elf creature until end of turn. It's still a land.

Douglas Nielsen