Unbreathing Horde is a rare Creature — Zombie card from Innistrad (ISD), collector number 121. Current market price: $0.43 (foil $4.98), TCGplayer market prices via Scryfall.
This creature enters with a +1/+1 counter on it for each other Zombie you control and each Zombie card in your graveyard. If this creature would be dealt damage, prevent that damage and remove a +1/+1 counter from it.