Cannibal

Flying, Annihilator 1, Ravenous X (Creature must
be a dragon and X is that dragon's toughness)
Cannibalism—{5}, Sacrifice another dragon: Place
two +1/+1 counters on Cannibal.
Whenever Cannibal blocks, becomes blocked, or is targeted by an ability of a dragon under an opponent's control, Cannibal gets +2/+2 until end of turn.
Whenever Cannibal kills another dragon place two
+1/+1 counters on it.