Magnets are fun. These magnets by United Nuclear, on the other hand, are no laughing matter. Check out this purchase disclaimer:
The magnets listed below are very powerful, much more powerful than magnets most people have seen, and need to be handled with proper care. Our larger magnets can easily bruise fingers and even break finger bones as they attempt to connect together. If you or someone in your household has a PACEMAKER or another electronic surgical implant, don’t even think of ordering these items. Neodymium magnets are not suitable for children to play with, and should only be handled under strict adult supervision.
Last month, the website cautioned that said magnets could “crush hands” and “cause things to go airborne,” but they’ve since updated their copy. Still hilarious. (Thanks, Matt)