Haunted Ruins

As Haunted Ruins enters the battlefield, you may
pay 2 life. If you don't, Haunted Ruins enters the battlefield tapped.

{t}: Add {b} to your mana pool.

{t}, Pay 2 Life: Exert Haunted Ruins: Add {b}{b} to your mana pool. (An exerted permanent won't untap during your next untap step.)