Viksil, Sewer of Skulls

Sacrifice a creature, {b/g}, {t}: Create two 0/1 black
and green plant creature tokens.
Whenever you sacrifice a creature, put a +1/+1 counter on each plant creature you control.

Viksil became obsessed with the Abzan's ability to
raise their dead as kin-tree spirits. His methods
were far more gruesome, and so were his results.