Neodymium magnets are the strongest type of magnets that are available commercially. Unsurprisingly, this means that they can be rather dangerous. In some cases, the magnets are able to hold more than 1,000 times their own weight. If you get your hand between two of them, that's a lot of crushing force. In fact, if these magnets are of the proper caliber, a row of them is powerful enough to affect the speed and angle of a steel bullet in mid flight.
If that's not impressive enough, neodymium magnets that are as large as the palm of a person's hand are strong enough to affect everything magnetic or electronic in a room, and these larger versions can't be transported by plane because their severe stregenth causes them to interfere with a plane's navigation system.
They are known as "rare earth magnets" because they contain elements from the periodic table that—you guessed it—are rare. Created in 1982 by General Motors, they are nearly always made of metal alloy containing neodymium, iron, and boron.
Here, you can watch as two super-strong neodymium magnets jump together in slow motion, destroying a variety of every day items.