Filth 
Creature — Incarnation
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.
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyLEGALvintageLEGALcommanderLEGAL