Feather Stars are also known as Crinoids. They are filter feeders with feather-like arms. They do have legs on the bottom and can move around. Here are some examples of them. Identification could take some time. Amami 2019
This looks like a Feather Star. Enoshima 2008
Feather Star on coral. Amami 2024
Feather Star on coral. Amami 2024
Here you can see a tiny leg of the feather star. Amami 2024
Feather Star Enoshima 2018