Kurang-ajar kids of unstable character or suffering from Borderline Personality Disorder (BPD) blindly imitating or 'copy-catting' the postures, behaviours and actions of Superman, Spiderman, Ultraman, Tarzan, Flying Kungfu Master or other fictional 'heroes' in books or movies could be harmful also to their own physical well-beings.

Borderline Personality Disorder
http://www.nimh.nih.gov/publicat/bpd.cfm