Fangs of Kalonia is a uncommon Sorcery card from Modern Horizons 3 (MH3), collector number 153. Current market price: $0.33 (foil $0.39), TCGplayer market prices via Scryfall.
Put a +1/+1 counter on target creature you control, then double the number of +1/+1 counters on each creature that had a +1/+1 counter put on it this way. Overload {4}{G}{G} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")