I know it's a long shot but I was reading through my Calvin and Hobbes treasuries when Calvin's transmogrifier gun caught my eye with its jutting straight barrel. So I started to thinking on whether it could, however unlikely, be based on a Walther P38. In the comic the gun is just an ordinary water pistol but, in later strips, most of the water pistols Calvin uses are ray gun-shaped and unmistakably un-gun like. And considering the strip was created during the middle of the 80's and the height of the Transformers craze it is somewhat poetic that a Transforming gun is what Calvin uses to transmogrify, or "Transform", things. And if there are any gun enthusiasts out there, are there any other guns that bear resemblance? I scanned a few images below, not the best quality though.