In my flat I had a normal hook for towels in the bathroom. And this one. It’s obviously just a part of whole hook, but other hooks are solid (can’t be disassembled). I found that it’s probably Gio Bella Riete collection, but didn’t found any possible match. Examples of other accessories from this collection:
My best guess, used to have a mirror you could pivot. The where was it located?
Or maybe one of those mini triple towel holders.