Someone you meet online in a game (Quake 3, for example) with a name spelt with capitals at random intervals, numbers, multiple colours if possible and an inprobably tough-sounding name. However, what truely makes a kiddie kicker is his real persona - an eleven year old boy from Minneapolis who's trying to avoid doing his homework and focuses his attention on whopping your ass.
"FeaR mE, fOr i aM bOw31 bu5T3r!"
"MARTIN! Have you finished your maths homework yet?"
"Not yet, mom."