Havenwood Vents
Land (Rare)

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

Tap: Add G or U to your mana pool.

Tap: Add 2 to your mana pool. Put Havenwood Vents on top of your library.

2: Havenwood Vents becomes a 2/2 green Beast creature until end of turn. It's still a land.

Mark Critchlow