Pyotr, Vildin Pack Stalker

Other wolves and werewolves you control get
+1/+0 for each counter on Pyotr, Vildin Pack
Stalker.
When Pyotr, Vildin Pack Stalker transforms, put
a +1/+1 counter on it for each creature with a
prey counter. Then Pyotr, Vildin Pack Stalker
fights each creature with a prey counter on it.
Regenerate it after each fight.
Nightbound