Gloomfang Mauler is a common Creature — Nightmare card from March of the Machine (MOM), collector number 108. Current market price: $0.27 (foil $0.28), TCGplayer market prices via Scryfall.
Swampcycling {2} ({2}, Discard this card: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle.) Backup 2 (When this creature enters, put two +1/+1 counters on target creature. If that's another creature, it gains the following ability until end of turn.) Menace