Visra, Essence Scourge

{t}: Reave target creature you control.
(For each colored mana symbol in that creature's mana cost, add one mana of that color to your mana pool. Then put that many
-1/-1 counters on it.)
Whenever one or more -1/-1 counters are placed on a creature you control, for each opponent, put a -1/-1 counter on target creature he or she controls.