Calythis, The Rubin Sorceress

Witchcraft — If there are six or more witches
on the battlefield under your control and/or in your graveyard, instants and sorceries in your graveyard have flashback.

{p/r}{p/r}, {t}: Copy target instant or sorcery. If
you control six or more Chaos tokens, the next instant or sorcery you cast may gain storm instead.