Officer Katz was one of three kidnapping victims by the Mad Hatter in one of his attempts to break Batman during the events of Halloween.
During the events of Scarecrow's attack on Gotham City on Halloween night, Katz was pursuing some rioters, however, his siren then started to malfunction, forcing him to pull over. Not long after he pulled over, however, he was knocked out by the Mad Hatter (who had been responsible for modifying his and two other police officers' squad car's sirens to implement a hypnotic tune), and then locked up inside the trunk of his own car while wearing a mask mirroring the Cheshire Cat from Alice's Adventures in Wonderland, with the trunk also being rigged with explosives to ensure Batman couldn't rescue him easily. Mad Hatter then had his car placed at the Miagani Island statue, also defacing his car with statements from the book. Batman ultimately managed to disarm the explosives and rescue Katz, who was baffled as to how he ended up on the statue before remembering he had been pursuing rioters before the sirens started acting screwy and relaying this to Batman. He was then brought back to the GCPD, where he was sitting in the corner due to the trauma of what he had to endure.
- His name is an allusion to the Cheshire Cat.