Molten Castle
Land (Rare)

Molten Castle enters the battlefield tapped unless you sacrifice a Red permanent.

Tap: Add R or W to your mana pool.

Put Molten Castle on top of your library: Add 1 to your mana pool.

RW: Molten Castle becomes a 2/1 red and white Elemental creature until end of turn. It's still a land.

Steve Deschamps