Gluttonous Slug is a common Creature — Slug Horror card from Modern Horizons (MH1), collector number 93. Current market price: $0.17 (foil $0.22), TCGplayer market prices via Scryfall.
Menace Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)