Scrap Trawler is a rare Artifact Creature — Construct card from Aether Revolt (AER), collector number 175. Current market price: $1.31 (foil $2.26), 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.