I am actually not certain of the 4chan meme origin, but I guess /b/ would be a fair to assume
This is also where you'll find Candleja- most of the time, although he's also seen in /co/...
I'll look and post if I can find anything more on the origins... in the meanwhile - enjoy a nice youtube clip:
YouTube - Freakazoid Episode 2 - Part 1 (as far as I know his first appearance, but this is pretty much all I've ever seen of Freakazoid, so i dunno)