Rust Harvester is a rare Artifact Creature — Robot card from Edge of Eternities Promos (PEOE), collector number 159p. Current market price: $0.24 (foil $0.31), TCGplayer market prices via Scryfall.
Menace {2}, {T}, Exile an artifact card from your graveyard: Put a +1/+1 counter on this creature, then it deals damage equal to its power to any target.