In my opinion, the biology of inkling and octoling and my fanmade species (axolotling) hair is odd.
Like what I think is that in order to get a haircut you need anesthesia and tourniquets
Because there's tons of blood vessels and nerves and muscles. Also, they can move their hair like another set of limbs.
And the hair feels a bit cold and a tiny bit moist to the touch, like a glass of water with condensation on it