Kid Vicious aka Benji Madden, is the lead guitarist/backup singer of the band Good Charlotte.
A child that from a very early age is dressed like a punk rocker by his/her parents. The parents themselves are usually punk rockers themselves, And most of the time the child will also adopt a "punk" attitude and spit on other kids and get in brawls with its peers, This term is also a reference to Sid Vicious The legendary bass player of the Sex Pistols.
A: Did you see Duane and Corey's son Clash?
B; You mean the kid with the studded pants and the ripped shirt that spit on another kid?
A; Yeah thats him. He is a regular little Kid Vicious!