This concept is extremely silly. It wouldn't work in any RPG setting remotely serious.
That said, I love silly stuff.
So let me chime in with my own ridiculous invention.
A small, water-stained paper flyer finds its way to your hands. There is a strange, spiked cannon-like contraption on it that looks like the unholy cross between a mortar and a cover for a heavy metal album depicted on it. By its side, there is a medieval-looking flail depicted with a rather large spiked steel ball and a single, smooth cannonball.
THE ADVANCED FLAILMASTER PRO 3000™
Are you tired of the logistics needed to supply your troops with melee weapons while they are in the middle of a heated battle? Are you fed up with those complaints about the poor quality of the equipment you're providing to your grunts? Are your ACME swords always breaking?
We have the solution.
The Advanced Flailmaster Pro 3000™ by NotMad Indsutrial™Industrial™ uses the incredible power of BLACK POWDER and SPRINGS to deliver a very dangerous load on the heads of your enemies and
qualityusable weaponry for your troops!Its special cannonballs are actually a very smart, spring powered device that unfolds itself into a heavy spiked flail upon launch. The spikes, chain and handle are held inside the shell of the cannonball by a delicate set of glass switches and powerful springs. With the power of the launch from the cannon body, the switches break, releasing the spikes and deploying the handle mid-air. When the weapon lands it inflicts not only heavy damage from the heavy iron object falling from the sky but also provides your army with bashing weapons to continue the fight.
And don't worry! The ADVANCED FLAILMASTER PRO 3000™ comes with a special Terms of Service agreement that forbids its deployed weapons to be used by your enemies! If one of them decides to use the deployed weaponry against you, you are entitled to sue them back!*
*Not actually guaranteed to work against barbarian lawless hordes and murderhobo adventurers. Or lawyers. Or, anyone, really. Just don't rely on this.