After she was cast, writer/director John Lechago, who is also an artist, told Victoria De Mare he wanted Batty Boop to look totally unique. So instead of designing a costume, he wanted her to be covered in full body paint. De Mare loved the idea, even after he told her she'd have to be totally nude during the application process. He did several make up tests until they found a design they both liked. After that, every day De Mare would show up on set and stand nude for 5-1/2 hours while makeup artist Tom Devlin applied the paint. Then it would take about two hours to remove it at the end of a day's shooting.
The language that the behemoth hobo clown "Punchy" speaks is an actual language, and not "made up". It is called "Carny lingo". Carny lingo is an alteration of English much like pig Latin. It is popular with professional wrestlers and it was Al Burke who suggested to have all of Punchy's lines spoken in it.
John Lechago originally wanted Killjoy to wear a jester's hat, but had to nix this idea when the hat wouldn't stay on Killjoy's head because of his crazy hairstyle.
Due to the extremely hot and humid weather, director John Lechago was not able to hydrate himself sufficiently. As a result, he developed a kidney stone that passed while shooting the final scenes. No one on the crew knew that John was in pain, even though he was pacing more than usual.