A Finnish reader named Ossi sent us a photo and some information on a rather outlandish Finnish weapon developed at the tail end of the Continuation War with the USSR. It was a standard m/31 Suomi submachine gun, but with the addition of an underbarrel flamethrower(!). It is not particularly uncommon historically for flamethrowers to be more or less disguised to look like regular rifles from a distance, to prevent the enemy from being able to easily spot the men with flamethrowers and concentrate fire on them. This one, however, is the only one I’m aware of where the flamethrower is attached to a fully functional firearm.
Apparently this was field tested in the summer of 1944, but never went into production. Apparently the only remaining example is on display at the Finnish Military Museum (Sotamuseo) in Helsinki.
Thanks for the cool information, Ossi!