Plaguing Abomination

Mutate {p/b}{p/b}{p/b} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Menace, Wither
When this Creature Mutates, you may divide X -1/-1 counters among any creatures, where X is the number of swamps you control.
Whenever a creature with a counter on it dies, add {b}.