Hmmm, maybe Squirrk or Trolcrusher? Or maybe The Freaky Little Monster?
I recommend to lock him in a dungeon too, you could also make an ancient glyph that you have to write "Cheese!" on it every 180 minutes so the glyph would stop the monster from escaping... or you could just... hmmm... drop him into bottomless pit where you throw away all your stuff...
Oh, I could teach that little... how was his name? Moron? Boron? Barney? So anyway I can teach him about lightning energy, mechanics and patent rights, Cavie can teach him how to use and make potions and make those badass jumps from window using graple hook. Oh, Clawren can teach him stealth and how to use rifles and other weapons...