How about dressing him up like a spider? It really simple. Put him in a black long sleeve shirt, black pants, black shoes. Paint his face black, get some mens black socks ( about the same lenght as your sons arms) stuff em with newspaper and attach them to the shirt so they look like spider legs. To form the socks to lok like legs, put a straightened out coat hanger inside the sock so you can bend it to hold shape.Paint a little red hour glass on the chest of the shirt. There ya have it! The cutest little black widow spider. You can even buy a toy bug and wrap it up in white thread to look like it was wrapped up in a web. Secure it to his wrist so it looks like he is about to eat dinner.
You can also paint little fangs on his face.
Or
Get some fabric of any primary color. Cut two big circles from the fabric, sew em together leaving spaces to put it on, and holes in the seams for arms, legs and head, paint a white M on teh front and back, paint his face to match. You just turned him into a sweet little peice of candy!
Can ya tell I like halloween costumes?