Corpse Constrictor

Whenever Corpse Constrictor attacks and isn't blocked, you may distribute X -1/-1 counters to
any number of creatures where X is Corpse Constrictor's power. If you do, Corpse
Constrictor assigns no combat damage this turn.
Whenever a creature with one or more -1/-1
counters dies, you may pay {2}{b}. If you do,
return a creature card from your graveyard to
your hand.