Cave Debris
Land (Rare)

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

1, Tap: Add RR, RU or UU to your mana pool. Cave Debris deals 1 damage to you.

1U: Cave Debris becomes a 1/1 blue and red Ogre creature with flying until end of turn. It's still a land.

Steve Tedin