Obsidian Creek
Land (Rare)

Obsidian Creek enters the battlefield tapped unless you control one or more creatures.

1, Tap: Add BB, BU or UU to your mana pool. Obsidian Creek deals 1 damage to you.

UB: Obsidian Creek becomes a 2/1 black and blue Rogue creature until end of turn. It's still a land.

Jesper Spencer