No, it is not a gun, or a plane. It's a can opener. Yes a can opener. A P-38 Military Can Opener to be exact. Yes, unless you have been in the Army, though I dont think they use them anymore (if I am wrong please correct me in the comments area), you might have not seen the style of one of these before. Sure there are the commercial hand held openers, but many of our veterans have sworn by these. Years ago these used to come in C-rations for opening the canned goods that came with them. The actual can opener itself is a little bit smaller than what the picture shows, it is exactly 2 inches long and an inch and an 8th wide. It is steel, with a 3/4ths of an inch curved claw blade that can open almost any can, and be used for other purposes too, like cutting things that need cutting, or used as a mini screwdriver. It is small, light, compact, and to me seems pretty tough and the hole on the end makes it so it could be put on a necklace or keychain. I tried it out on a can of tuna for my lunch yesterday. This is a useful little tool.
BTW, I bought 15 of these for $7 total at amazon, though supposedly many have lasted a lifetime for our veterans.
Go here for more information on this little tool at Wikipedia. There is another link on that page to Georgia Outfitters where they have veterans stories on how this little tool was used too in the resources area.