Horned is the boss of Magical Island.
The boss of this island is a large version of the demon that appears in Fairyland Story when you take too long to clear a screen. This version of the demon moves very much like the Helicopter boss of the second island, but faster. He horizontally from side to side, occasionally adjusting his height before resuming his movement. From time to time, he stops and throws his blue pitchfork across the screen. In order to fight him effectively, try lure him to the bottom so that you can get up above him, create some rainbows, and crush them on him before you get out of the way when he rises back up. Then repeat the process. It's important to give yourself enough time to move out of the demon's path; don't wait until the last second or you will have no room to get clear (unless you have the wings and can climb even higher than the platforms allow.)