Scrap Trawler is a rare Artifact Creature — Construct card from The Brothers' War Retro Artifacts (BRR), collector number 112. Current market price: $4.32 (foil $5.75), TCGplayer market prices via Scryfall.
Whenever this creature dies or another artifact you control is put into a graveyard from the battlefield, return to your hand target artifact card in your graveyard with lesser mana value.