Filth is a uncommon Creature — Incarnation card from Judgment (JUD), collector number 66. Current market price: $8.30 (foil $51.41), TCGplayer market prices via Scryfall.
Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.) As long as this card is in your graveyard and you control a Swamp, creatures you control have swampwalk.