Menhphis, Death's Shadow

When this creature enters the battlefield, destroy X permanents and you gain X life.
When this creature leaves the battlefield, put X +1/+1 counters on target creature.
Flying, Deathtouch, Lifelink

"I am the beast of unfair,is it fair I destroyed Avacyn? Is it fair to die? I come to creep each day and night, I will reach you too!"