Abyssal Animation

Whenever an opponent mills one or more non- Abyssal creature cards, you may exile one of
those cards. Until the beginning of your next end
step, you may cast a creature card exiled with
Abyssal Animation and you may spend mana as
though it were mana of any color to cast that
spell. That creature is a blue and black Abyssal in addition to its other types and colors.
Many of the creatures from the Abyss look remarkebly familiar to those dwelling near the surface...