Gunpowder Keg

{1}, {t}: Gunpowder Keg enters the battlefield tapped under target player's control.
If Gunpowder Keg would be discarded for any reason or if the player controlling Gunpowder Keg takes damage from any spell with {r} in its mana cost, then the player controlling Gunpowder Keg sacrifices it, sacrifices a land, and loses 5 life.