When is a gun not just a gun? When it lives between a character's legs and not in a holster, as seen in artwork from more than just a few video games.
There's a growing collection of not-so-subtle imagery over at Phallic Videogamery that shows how some video game artwork over the decades has fashioned various weapons into pseudo-penises. (This is different than players using in-game tools to create johnsons of their own.) Phallic Videogamery is young yet so please feel free to share artistic examples of crotch weapon design in the comments below.