Colin is a movie-fanatic like his father. He gets so emotionally invested in the films he watches. Every time a movie is ramping up to the climax, he starts to bounce on the couch, and minute by minute he gradually goes from sitting to kneeling to crouching, to a final leap up on the couch as the hero triumphs.
He also loves to experiment with delivering the dialogue. I couldn't even guess as to why he's doing it, or what is behind it. But he will sit and watch a movie and imitate each line spoken, along with any little hand gesture or facial expression or voice modification. His eyes are glued to the screen in complete focus.