Baxter Stockman is a uncommon Legendary Creature — Human Scientist card from Teenage Mutant Ninja Turtles (TMT), collector number 139. Current market price: $0.15 (foil $0.25), TCGplayer market prices via Scryfall.
When Baxter Stockman enters, create a 1/1 colorless Robot artifact creature token. At the beginning of combat on your turn, target artifact creature you control gets +3/+0 and gains first strike and vigilance until end of turn.