Crazed Devourer

Devour N. (As this object enters the battlefield, you
may sacrifice any number of creatures. This
permanent enters the battlefield with N +1/+1 counters
on it for each creature sacrificed this way.)
When Crazed Devourer kills a creature, exile it
and place a +1/+1 counter on Crazed Devourer.
{t}: Remove X +1/+1 counters on Crazed
Devourer. You gain X life.