Shaun, Father of Synths is a rare Legendary Creature — Human Scientist card from Fallout (PIP), collector number 119. Current market price: $0.31 (foil $1.67), TCGplayer market prices via Scryfall.
Whenever you attack, you may create a tapped and attacking token that's a copy of target attacking legendary creature you control other than Shaun, except it's not legendary and it's a Synth artifact creature in addition to its other types. When Shaun leaves the battlefield, exile all Synth tokens you control.