CAUTION: LOOK OUT FOR FALLING SPOILERS.
Pretty much the last person I would have suspected of being a secret robot was Bernard, the thoughtful, morally upright right-hand man to Robert Ford in Westworld. That was the big reveal in episode 7, Trompe L’Oeil.
Equally shocking was Bernard bludgeoning Theresa to death with apparent super-human strength, on the orders of Ford. At least he took her out for lunch first. But is she really dead? The HBO web site has Theresa (Sidse Babett Knudsen) down for nine episodes.