I think the weirdest thing I ever used was a regular garden hose (old school, rubber hose with brass nozzle). I was much younger, but I remember a bully threatening my brother with a pretty good sized club (made from a branch as thick as a baseball bat).
With him being armed, I decided to level the playing field, and grabbed up a hose. At first he laughed. Until he was bleeding all over (from the metal tip) and black and blue from the hose itself. (I first used the hose like a whip to disarm him of the club). Like other bullies I'd bested (just a few) in the past, we actually became friends later on.