Overgrowing Undead

Whenever a Zombie enters the battlefield, put
two +1/+1 counters on Overgrowing Undead.
Remove a +1/+1 counter from Overgrowing
Undead: Destroy target non-Zombie creature.
"There are some things even I am afraid to rise again," said Liliana. "Even if it is for the greater good.""Even more of a reason to keep an eye on you." said Gideon.