Answer: acanthocephales (thorny-headed worms)/phylum Acanthocephala
Congratulations to "Anonymous" and Alasdair who got this correct right away. In the words of Alasdair "Acanthocephales, and such a beautiful parasite (if I may say so!)".
It definitely is a striking appearing parasite, as the thorny head is quite apparent.
Acanthocephala are parasites of fish, as Alasdair mentioned, but they are also parasites of other vertebrates, including pigs, rats, and (rarely), humans. The most common ones to parasitize humans are Moniliformis moniliformis and Macracanthorhynchus birudinaceus.
Humans acquire this infection through ingestion of various beetles and cockroaches which are the intermediate host for these parasites.
Thanks for writing in with your comments!