Help identify something.

Chelsea567

Good day. I discovered a new hydrobiont. It looks like a translucent black worm with many circles around it. If you blow on it with a stream of water from a pipette, it contracts and hides the circles. Sorry for the quality of the photo, but it’s the best I could do. Maybe someone knows what kind of creature/sponge/worm this is?

David

The beast has been identified. It is the colonial ascidian Botryllus. It has already grown three times larger. Here is the most similar photo. Mine is less white.