This slip up happens during the scene where the Ghost of Christmas Past appears to him in the bedroom. She has this cone that they want you to believe is suspended in mid air by her hand. Now, look closely. The cone is suspended by a thin fishing line. At the beginning, she steadies it between her fingers. When she takes her hand away however, she accidentally moves the line and the cone weaves back and forth. Watch the top of the ball on top..you can clearly see the line and the movement.