Walter (Robot of Sherwood)
From Tardis Wiki, the free Doctor Who reference
Walter was a peasant who was forcibly taken for labour at a spaceship disguised as a castle by the Sheriff of Nottingham in or around 1190 so that the Sheriff could rule the Earth. Maid Marian tried to help him up when he collapsed from exhaustion while gathering gold to power the Sheriff's spaceship, but a robot knight analysed Walter's usefulness as "expired" and blasted him into ash with a laser. (TV: Robot of Sherwood)