Grakmaw, Skyclave Ravager

Grakmaw, Skyclave Ravager enters the battlefield
with three +1/+1 counters on it.
Whenever another creature you controls dies, if
it had a +1/+1 counters on it, put a +1/+1 counter
on Grakmaw.
Whenever Grakmaw dies, create an X/X black
and green Hydra creature token, where X is the
number of +1/+1 counters on Grakmaw.