(Clavelina cyclus) ワモンツツボヤ
I think this is Clavelina cyclus which is a blue tunicate with a yellow ring around the large siphon. Amami 2022
A colony of Clavelina cyclus. Amami 2023
A closer look at Clavelina cyclus. Amami 2024
Clavelina cyclus sometimes will have a yellow stripe on the side. Amami 2026