Profane Amulet

At the beginning of your upkeep, if Profane
Amulet is tapped, add {c}. Until end of turn, you
don't lose this mana as steps and phases end.
{t}: Put a stun counter on Profane Amulet. It
deals 1 damage to you. Activate only as a sorcery.
"A stimulus that invokes great ambition, granted to
those who desire it the most."
—Amulet inscription