Gutterbones is a rare Creature — Skeleton Warrior card from Ravnica Allegiance Promos (PRNA), collector number 76p. Current market price: $1.05 (foil $2.75), TCGplayer market prices via Scryfall.
This creature enters tapped. {1}{B}: Return this card from your graveyard to your hand. Activate only during your turn and only if an opponent lost life this turn.