Corpsejack Menace is a rare Creature — Fungus card from Return to Ravnica Promos (PRTR), collector number 152★. Current market price: — (foil $1.84), 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.