Slagheap Flats
Land (Rare)

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

Tap: Add R or W to your mana pool.

1R: Slagheap Flats becomes a 1/1 red and white Goblin creature with first strike until end of turn. It's still a land.

John Critchlow