The Apache Revolver was essentially a weaponized version of the concept behind the Swiss army knife. It crammed a whole bunch of ways to hurt people into one easy to carry and conceal package with a fold-out design, specifically a gun, a knife, and a set of brass knuckles. It couldn't do the job as well as any of these individually but, if efficient use of space was your thing and you lived in the late 1800s and early 1900s, this might have been the weapon for you.
The design started with the cylinder and safety of a revolver. To this, where most guns would usually have a handgrip, was the knuckleduster, which would fold back underneath the cylinder, so the user would wrap his hand around the cylinder during melee combat. The knife blade was attached with a hinge to the underside of the cylinder and was usable as a sort of bayonet or, with the gun in folded position, by itself.
Unfortunately, to make such... utility possible, the gun conceded the use of a barrel, making it extremely inaccurate. This made it extremely unpopular with almost everybody except the eponymous Parisian gang from which the gun took its name and, supposedly, British commandos in World War 2 who are said to have used a 9mm variation on the weapon. This makes some degree of sense- commandos needed several types of weapons and a minimal load to carry.
Ultimately, the weapon was destined to fade into obscurity, doomed by its general impracticality to become a footnote in firearms history. It is still possible to buy one online however, should you ever need to shoot, stab, and bash someone to death.
An ornate example of an Apache revolver.