Misty Rainforest
Land (Rare)

At the beginning of your end step, if you didn't cast any spells this turn, Misty Rainforest deals 1 damage to you.

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

1U: Misty Rainforest becomes a 1/1 green and blue Merfolk creature with flying until end of turn. It's still a land.

Steve Briclot