Robo- is a uncommon Artifact Creature — Construct card from Unstable (UST), collector number 157. Current market price: $0.13 (foil $0.44), TCGplayer market prices via Scryfall.
At the beginning of each end step, if an artifact entered the battlefield under your control this turn, Augment {2} ({2}, Reveal this card from your hand: Combine it with target host. Augment only as a sorcery.)