Ominagi, Shaded Sanctuary

Ominagi enters the battlefield tapped.
{t}: Add {b}
Serenity (Whenever you cast an instant or sorcery
put a Serenity counter on it.)
{t}, Counter a spell you control with a Serenity
counter on it : Each opponent loses one life for
each Serenity counter on the countered spell, you
gain that much life.