Ogan Spellbane

Whenever an opponent casts a spell, Ogan
Spellbane deals X damage to that player where
X is the amount of colorless mana spent to cast
Ogan Spellbane.
{1}{w}{t}: Ogan Spellbane loses all non-mana
abilities and becomes a noncreature artifact
until an opponent casts a creature spell.
{t}: Add {w},{r} or {g}.