Shavka, Muse of Trade

Whenever an opponent casts a noncreature spell,
draw a card.
Whenever a creature attacks you, create a
Treasure token. (It's an artifact with "{t}, Sacrifice
this artifact: Add one mana of any color.")
{w}{u}{b}{r}{g}, {t}: Choose a nonland card you own
from outside the game or in exile. You may cast
that card this turn without paying its mana cost.