Kiru, Light of the Moon

At the beginning of your precombat main phase,
put a phase counter on Kiru. Then if there are
four or more phase counters on her, remove
them all and draw two cards. Otherwise, add
that much mana of any one color.
{x}{w}, {t}: For each phase counter on Kiru, target
opponent sacrifices an artifact, creature, or
enchantment with mana value X or greater.