He’s not badly behaved; he’s just got an oddly coloured chakra:
Indigo children were first described in the 1970’s by a San Diego parapsychologist, Nancy Ann Tappe, who noticed the emergence of children with an indigo aura, a vibrational color she had never seen before. This color, she reasoned, coincided with a new consciousness.
In “The Indigo Children,” Mr. Carroll and Ms. Tober define the phenomenon. Indigos, they write, share traits like high I.Q., acute intuition, self-confidence, resistance to authority and disruptive tendencies, which are often diagnosed as attention-deficit disorder, known as A.D.D., or attention-deficit hyperactivity disorder, or A.D.H.D.
[thanks to Claire]