Gluttony Maw

Flying (This creature can't be blocked except by creatures with flying and/or reach.)
Devour 2 (As this creature enters the battlefield, you may sacrifice any number of creatures. This creature enters the battlefield with twice that many +1/+1 counters on it for each creature sacrificed this way.)
If Gluttony Maw is devoured, move all +1/+1 counters from it to the creature that devoured it