Avernus, The desert of fire

Avernus, The desert of fire enters the battlefield tapped. Whenever a mountain or swamp enters on the battlefield under your control, untap Avernus, The desert of fire.
{t}: Add {r} or {b} to your mana pool
{2}{r}{t}: deals 2 damage to target creature
{3}{b}{t}:Destroy target creature that was damaged this turn