In his 1983 fake documentary 'Zelig', Woody Alan plays a character, Leonard Zelig, a kind of human chameleon who takes on the appearance and behaviour of whoever he is with. Now
psychologists in Italy have reported the real-life case of AD, a 65-year-old whose identity appears dependent on the environment he is in. He started behaving this way after cardiac arrest caused damage to the fronto-temporal region of his brain.
Comment: Strange... it sounds a lot like psychopathy.