Can a gun get any uglier and unwieldier? Enter the Armaguerra OG-43.
It's an Italian submachine gun chambered in 9mm and uses a simple blowback action. It fires from an open bolt at about 500–600 rounds per minute. Typically standard weapon of its time, what is unusual would be the stock and folding grip, making it somewhat compact and lightweight.
The stock can be folded back alongside with its grip to make it a more compact looking weapon to store. It feeds from a 20 round magazine and as well as a jerryrigged 30 round magazine.
Due to its awkward handling, the "bolt handle" can be seen at the top, looking like a pair of wings or ears that the user needs to tug back to rack the gun.
It only has a muzzle attachment.
Model from thomasvivash (Sketchfab), thank you Riceler for the support!