Poultice Sliver is a common Creature — Sliver card from Planar Chaos (PLC), collector number 11. Current market price: $0.25 (foil $4.30), TCGplayer market prices via Scryfall.
All Slivers have "{2}, {T}: Regenerate target Sliver." (The next time that Sliver would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)