Gunther Hardwicke was The Shark, one of the Terrible Trio.
Gunther Hardwick, a young heir to a shipping company, joined Warren Lawford and Armand Lydecker in the Terrible Trio, under the respective names of Shark, Fox and Vulture. Shark assisted his allies in various heists. After a confrontation with Batman and Robin, he actively participated in the attack on Sheldon Fallbrook.
When Sheldon's daughter and Warren's girlfriend Rebecca realized their identities and crimes, Shark and the Trio tried to kill her, but they were evidently stopped by Batman. Shark then tried to engage in combat with Batman one-on-one, but was quickly beaten and then sent to prison.