Shaun, Father of Synths is a rare Legendary Creature — Human Scientist card from Fallout (PIP), collector number 429. Current market price: $1.03 (foil $1.82), 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.