Iron Man (Marvel)

 Iron Man (real name Tony Stark) is one of the msot well known superheroes in comics and Marvel. Iron Man is also known for being one of the founding members of the Avengers. At one point, Stark's armor becomes sentient despite fail-safes to prevent its increasingly sophisticated computer systems from doing so. Initially, Stark welcomes this "living" armor for its improved tactical abilities. The armor begins to grow more aggressive, killing indiscriminately and eventually desiring to replace Stark altogether. In the final confrontation on a desert island, Stark suffers another heart attack. The armor sacrifices its own existence to save its creator's life, giving up essential components to give Stark a new, artificial heart. This new heart solves Stark's health problems, but it does not have an internal power supply, so Stark becomes once again dependent on periodic recharging. The sentient armor incident so disturbs Stark that he temporarily returns to using an unsophisticated early model version of his armor to avoid a repeat incident. He dabbles with using liquid metal circuitry known as S.K.I.N. that forms into a protective shell around his body, but eventually returns to more conventional hard metal armors.