Fan Nickname: The yellow gun is called "The Butter Gun" by some as dragged lines of yellow blocks look like sticks of butter.
Urban Legend of Zelda: Some cheat code sites say pressing ESC before capturing the black cube entity will allow you to retain the black gun. This is a cheap trick to get you sent back to the starting chamber when you're about to win. There is no known way to retain the black gun after the end of the game. You can turn your gun black this way, but it gives you no special abilities aside from leaving black cubes and when you restart the game your gun will be red again.