Safe from impact, safe from extreme temperatures, and just plain fun to watch
Here is the non-scientific, fantasy explanation of what's going on in this video: Scientists have discovered a way to breed a ball bearing with Silly Putty.
Here is the scientific answer: Researchers from RMIT University call these little marvels "liquid metal marbles," and they're drops of liquid metal with a nanoparticle coating. They're both heat- and impact-resistant (see above), and researchers say their conductive cores could be used for flexible electronics in the future.
That is, if the researchers, unlike me, can stop watching this video.