Skaab entangler

Skaab entangler enters the battlefield with X +1/+1 counters on it where X is the number
of creature cards in your graveyard whenever
a creature dies put a number of +1/+1 counters on Skaab enangler equal to it's toughness when Skaab entangler leaves the
battlefield you gain life equal to it's
toughness