Marrow-Gnawer is a rare Legendary Creature — Rat Rogue card from Bloomburrow Commander (BLC), collector number 79. Current market price: $23.40 (foil $23.05), TCGplayer market prices via Scryfall.
All Rats have fear. {T}, Sacrifice a Rat: Create X 1/1 black Rat creature tokens, where X is the number of Rats you control.