Vitium, Umbra Incarnate

Polarity 5 (You may pay up to five mana in any
combination of colors in addition to this spell's mana
cost when casting it. If you do, this spell's color
identity becomes each color of mana paid this way.
Otherwise, its identity is colorless.)
Flying, First-Strike
Vitium, Umbra Incarnate gets +1/+1 for each
color in its color identity.