Marrus orthocanna. A deep sea siphophore, ie. a colonial cnidarian.
These things have a tiny float at the top to make sure they don’t sink to the bottom of the sea.
Beneath that are a whole load of nectophores that look like jars and act just like jellyfish so that the whole colony can swim around.
Trailing behind it is a good 1 or 2 metres of polyps and stinging tentacles for catching prey.