Corpsejack Menace is a uncommon Creature — Fungus card from Iconic Masters (IMA), collector number 197. Current market price: $0.80 (foil $1.66), TCGplayer market prices via Scryfall.
If one or more +1/+1 counters would be put on a creature you control, twice that many +1/+1 counters are put on it instead.