I founda GIF online with a triangle tunnel. But it was not spinning, and I did not like that. So I brought it into scratch, looped throuch the costumes and spun it a few degrees each costume change. The reason its a circle is because if you take it away, you see it spinning. TTo try it out, just press See Inside, and delete the second sprite. Then look in the corners.
This is a GIF from the internet, that I modified so it spins.
