Not one but two stars. The serpents always know when an octo is in residence and park themselves near by to collect food scraps but this is the first I have seen introductory behavior from other stars. In the smaller video it is harder to see and I did not see it live but there is a brittle star also checking out the new octo. If you watch carefully, you will see the throny moving its arms to check out the suckers but the brittle also checks out the webbing. When the brittle touches the arm at the webbing is when the octo did its stress dance. The thorny moved on just after the video but the brittle continued to seek for awhile. They may have only been looking for food scraps but I have not seen them do this with the other two octos that lived in the same tank.