Well, I can't show you the picture of this guy. You'll have to play it to find out what he looks like. But, I can still tell you how to kill it.
Who would think that fighting fire with fire would work? Well, it does, because Hot Head is only vulnerable to the Fire Rod. Your general strategy should be to fire off as many shots per second as possible. Don't let up. If a fireball comes toward you, move and resume firing. He'll be gone shortly.