Haruko from FLCL. I'm screwed. Unless you wanna count Naoto as the main character; in that case, bring it on >:D NOTE: I've only seen the first OVA. Hopefully Naoto's robots from his brain don't side with him or something.
Gon from HunterXHunter. If we're talking about his current state in the manga where he doesn't have any aura abilities right now, then I'm probably safe from a little kid. If it's the anime, then I guess I'm pretty screwed.