This was a story from the time when Clark Kent was Superbaby - I'm guessing a few years old but not in school yet. A group of three criminals disguised with pumpkin heads separately hold up a bank, a jewelry store and a museum, then rendezvous at a futuristic city built outside of Smallville as a prop for a movie. The movie was never made but the city and the props remained after the director died. The Pumpkin Gang are using it as a hide-out but little Clark is using it as an amusement park. When the crooks try to shoo the kid away they try out some of the science fiction props and they appear to work because Superbaby employs some of his developing super powers. For example, when the gang employs an invisibility projector the noise it emits scares the tyke and he flies away at super speed, making it appear the kid became invisible. Police officer Parker stumbles upon the activity and ends up being quite the hero by "single-handedly" apprehending the gang - with just a little bit of surreptitious aid from the tyke of steel. This was a long-term project because I had bodies I could use but finding three pumpkin heads that would fit them was the problem. The bodies, from left to right, were from Bruce Wayne, Toht and The Question and the pumpkins were from a variety of sources.