Duo Halloween Costume: Ron and Harry From Harry Potter No list of duo costume ideas is complete without our favourite Gryffindor besties, Harry and Ron. Their Hogwarts uniforms are pretty easy to re-create at the last minute. What to wear for Ron: Wear black trousers and a cape over a white dress shirt, grey vest, and tie. Make a wand. What to wear for Harry: All the above, but add some round-framed glasses and draw the lightning-bolt scar on your forehead. Image Source: Everett Collection