Reptilian poseur

Someone that spends most of their life trying to coup somebody else's life and get credit for living their life rather than doing things that actually interest them or what they really wanted to do as a kid. Someone that says they are passionate about music for example (despite not really holding anything sacred) and wants to become a musician not because they actually love music, but mostly to coup the life of someone they know who thought about becoming a musician when they grew up, discouraging the other person from ever trying or even thinking there is a point once they know it will only become another pointless battle for supremacy or some other bullshit their best efforts will get turned into that make the entire thing something other than a party or anything else fun or exciting that it seemed to be when it started out.