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:
it looks like the base of one of those dual swivelling towel holders like this: https://www.manomano.co.uk/p/towel-rail-double-swivel-wall-mounted-stainless-steel-foldable-swing-towel-holder-space-saver-rack-bathroom-kitchen-50cm-71536221