Funny, just thought of a costume, kinda morbid though. A take off on the Headless Horseman. The Headless Mini Biker.
On a dark and foggy Halloween, the Headless Mini Biker rises to ride the streets of this quiet little town, raiding the candy from unsuspecting children and old guys with baskets of the stuff. Muh hah hahahh ahah !
Or maybe, how bout Ghost Rider, as a kid on his mini bike.