| Aspect: | Tiny solitary polyp (although several can be present) with thin translucent tentacles atop a translucent jellyish stem attached to sponge surfaces. |
| Population: | Probably more common than it seems due to its very stealthy nature and small size (1cm). |
| Notable feature: | Comparatively large berry-like pink polyp head (gonophore, the gamete-producing organ), tentacle ends do not curl unlike those of other hydrozoans. |
| Environment: | Lives on sponges. |
| Behaviour: | Stings skin. |
