After the Mad Hatter disappeared following his debut appearance, an Imposter Mad Hatter appeared in Detective Comics #230 in April 1956. Unlike his predecessor, he was sane, sported a gaudy mustache, and primarily operated as a thief, apparently obsessed with completing his private collection of hats from all nations, cultures, and historical periods. He often constructed various weaponry concealed inside his hats, such as flamethrowers and buzzsaws. Unsurprisingly, the piece of headgear the Imposter Mad Hatter wanted the most was Batman's cowl. Once, he successfully removed Batman's cowl by spraying it with a radioactive substance, causing the Caped Crusader to take it off. No sooner did the Imposter Mad Hatter put it in his collection than Batman and Robin arrive. They had traced the cowl with their "super-sensitive Geiger counter" in the Batplane.