Zira, Mind Cleanser

Deathtouch, Menace
Whenever Zira deals combat damage to a player,
that player exiles cards from the top of their
library equal to the damage dealt. You may cast
those cards, and you may spend mana as if it
were mana of any color to cast those cards.
Whenever you cast a spell from exile, put
a +1/+1 counter on Zira.