It's a threaded sphere with a Phillips head.
I'm not going to lie, removing the supports from between the threads is a bit of a challenge.
UPDATED 2020 May 22: Resized the STL and the model now prints almost 2" or 5cm across. I still have to fix the places where the threads meet the Phillips head.
The author marked this model as their own original creation. Imported from Thingiverse.