Bloatfly Swarm is a uncommon Creature — Insect Mutant card from Fallout (PIP), collector number 42. Current market price: $1.73 (foil $3.87), TCGplayer market prices via Scryfall.
Flying This creature enters with five +1/+1 counters on it. If damage would be dealt to this creature while it has a +1/+1 counter on it, prevent that damage, remove that many +1/+1 counters from it, then give each player a rad counter for each +1/+1 counter removed this way.