In the days single-shot firearms, a pistol was of limited use against multiple opponents. That's why many came with built-in clubs.
This design, dubbed the "duck's foot" due to its shape, was one response developed in the Eighteenth and Nineteeth Centuries. People who needed to intimidate groups of foes, such as prison guards, carried it. Firing this flintlock pistol once would send four balls across a wide area.