Atrix, Locus of Blight

Whenever a creature you don't control gets
-X/-X until end of turn, you may put X -1/-1
counters on it instead.
Whenever Atrix, Locus of Blight blocks or
becomes blocked by one or more creatures, those creatures get -Y/-Y divided as you choose among
them, where Y is Atrix, Locus of Blight's power.