It seems hard to believe now, but the fat, loveable and almost harmless Mario was once planned to have a beam gun and rocket pack. Not very harmless then, eh? This trivia was found in the original developer's notes for Super Mario Bros. which turned up online about two years ago. Luckily, Nintendo soon realised that people thought they were more skilful when jumping on Goomba heads instead of blowing them up.
Image from http://www.wiiplaygames.com/2010/12/28/mario-had-a-gun/
Of course, this all brings up the question- Would you still like Mario if he had a gun and blew things up?
I definitely wouldn't, as that would mean that Mario games would probably now have evolved into First Person Shooters instead of racing, sport and platforming games.