Caldera Fields
Land-Mountain Plains (Rare)

(Tap: Add R or W to your mana pool.)

Caldera Fields enters the battlefield tapped unless you reveal an artifact creature card from your hand.

2, Tap: Target land becomes a 3/3 red Giant creature until end of turn. It's still a land.

W, Tap, Sacrifice Caldera Fields: Prevent all combat damage that would be dealt this turn.

Greg Chan