Sheoldred, One with Phyrexia

Swampwalk, infect
Sacrifice a creature or land: Nonbasic lands become Swamps until end of turn.
If Sheoldred, One with Phyrexia deals combat damage to an opponent or planeswalker: return a creature or planeswalker from either graveyard to the battlefield at random. It becomes Black and is an artifact in addition to its other types.