Jellyfish is in fact a name of a free-swimming phase in the Medusozoa life cycle.
The term “jellyfish” is commonly used to describe a marine animal, distinguished by its umbrella-shaped bells and tentacles, but it is in fact a predatory, sexual stage of medusozoan cnidarians.
It is called spraint and emits a smell, described by some scientists as similar to jasmine tea or violets. Otters use spraint to communicate with each other.