I just bought one too. It’s a rechargeable vibrating ball to roll your back, IT, calves, quads etc. Pretty cool because you can just grind it in and let the motor do the work.
Funny thing is I had a similar idea a few years ago using an orbital sander, which I installed a foam pad for my Achilles. But this Hypersphere is way better because you can use it like a conventional foam roller.
I’ve been doing 1-2 sessions per week at the gym with a good PT. Lot’s of single leg, ankle work and it’s improved my running stability or platform immensely. Still lots of work to do for next season.