Sigil of Malice

Whenever an opponent taps an artifact for mana,
gain 2 life.
{t}: Add {b}, {r}, or {g} to your mana pool.
If you gained life this turn and Sigil of Malice is untapped, Whenever a creature an opponent
controls enters the battlefield, destroy it.
Whenever an opponent casts a creature spell,
untap Sigil of Malice.