The body is made of two stainless steel hemispheres. One is plain and the other has holes for screws/screen. The hole for the screen was cut on a lathe. Surprisingly tricky to fixture - having the chuck point spread out instead of clamping down worked best. There's a piece of laser cut acrylic in front of the screen.
For the electronics, it is powered by an Adafruit QtPy S3. Initially I tried with an RP2040, but display updates were too slow for smooth animation with CircuitPython. (I'm sure in C or Rust, the RP2040 would be fast enough, but I wanted to livecode it if I could)
The accelerometer / gryo allows it to react to being bumped or spun. It also has capacitive touch with works reliably to detect petting it.
I took it with me to Fanime, with magnets to keep it on my shoulder. But... it fell a few times and eventually the magnets broke.
Real magnets are somewhat fragile, so I made my own from aluminum on a mill.