Dani, whom the article mentions, has also worked on prosthetic arm replacements which are indeed modelled on tentacles. I don't have a link to hand but I'm sure some use of your favourite search engine would show this for you.
I am unsure I want to search for images of tentacle arm replacements.
Why, oh why do I have to click on every link I see????
I'm wondering if you could get so used to it over time you would develop a 'ghost limb' syndrome, i.e. some discomfort/itching/confusion when the appendage is taken off.
I think you mean ‘phantom limb’.
How would you build a controllable tentacle? Here they control the thumb with two toes. An octopus tentacle would be way more complicated. Maybe with a Neuralink