Mario Kart 64 debuted one of the more useful items in the Mario Kart universe, the Blue Shell. The Blue Shell seeks out and blows up the person who's in first place. So, if you're in first place they're not too helpful, I guess.

But, they're kind of powerful, so to offset that, they're kind of rare. But, wouldn't it be nice if you could get them any time you wanted?

Well, then good news for you!

Certain tracks have mystery blocks that contain these missiles pretty well all the time, but the thing is you have to work a little harder to get at them.

Take Luigi's Raceway, for example. There's this block hanging from a giant balloon (not so giant in this picture, but it's hard to get a decent picture of it)

Your timing has to be pretty good, but if you can hit it...

Blue shell for you!

Just don't shoot it if you're already in first place... that's not recommended.

Unless you're so far in the lead that you can afford to take a hit like that and still win the race. Of course, then you're being a jerk... which is kind of fun sometimes.