Ray Dennis Steckler tried to make a straight crime drama. After shooting about 40 minutes of footage, he decided the film was simply not working. He couldn't afford to scrap the footage, and portions of the film were unintentionally funny, so he had two characters go into a room, then burst forth in makeshift costumes as Rat Pfink and Boo Boo. He padded out the rest of the film with chase scenes, fight scenes, and even an encounter with a gorilla. He shot footage of the duo appearing in a real-life parade, as if it were being held in their honor. When the main title was being animated, the "n" and "d" were accidentally left out, so the title appears as "Rat Pfink a Boo Boo."
A poster for Ray Dennis Steckler's previous movie, The Incredibly Strange Creatures Who Stopped Living and Became Mixed-Up Zombies!!? (1964), can be seen on the wall in one scene. Additionally, a girl wears one of the monster masks from that movie at a pool party scene.
When the kidnappers open the briefcase containing comics, the most visible magazine is Issue #2 (January 1965) of "Monster World," published by Warren and featuring the cast of Les monstres (1964) on the cover. Monster World was a sister publication of Famous Monsters. While Famous Monsters had a long distinguished career, folding only when Warren went under, Monster World didn't last as long.