Hardened Scales is a rare Enchantment card from Double Masters 2022 (2X2), collector number 151. Current market price: $3.45 (foil $4.15), TCGplayer market prices via Scryfall.
If one or more +1/+1 counters would be put on a creature you control, that many plus one +1/+1 counters are put on it instead.