They use proteins similar to those used by other animals, but for different things. Some people think they evolved muscles and nerves entirely independently of other animals. Some people think they fell from the sky.
Whatever you think, they are astonishing in every detail. Watch videos of Beroe if you have any doubts.
Ctenophores are a nigthmare to study. They self-disintegrate at the slightest touch and aren't well adapted to low pressure environments. Pieces of an animal being dragged from a storm before to fall again does not count as a realistic way to spread.
If you mean that they could have an extraterrestrial origin, is really unprobable IMHO. If there is an animal badly adapted to survive in the space is this.
https://www.goodreads.com/quotes/6870748-yes-sir-but-the-lib...
[1]: https://en.wikipedia.org/wiki/16S_ribosomal_RNA
A brief search didn’t yield anything on jellyfish phylogeny for me, would be curious if anyone else has information on this.
https://oceanexplorer.noaa.gov/fsts/media/DNAbarcodingCnidar...
https://www.farmersalmanac.com/maple-copters-everywhere-2158...
The Categories Were Made For Man, Not Man For The Categories
https://slatestarcodex.com/2014/11/21/the-categories-were-ma...
Enter the kangaroo.