Soulstinger is a common Creature — Scorpion Demon card from Amonkhet (AKH), collector number 108. Current market price: $0.18 (foil $0.42), TCGplayer market prices via Scryfall.
When this creature enters, put two -1/-1 counters on target creature you control. When this creature dies, you may put a -1/-1 counter on target creature for each -1/-1 counter on this creature.