"Immortal Coil" (or Star Trek: Immortal Coil) was the seventh spin-off of Star Trek: Phoenix-X and sixth spin-off of the third season. It originally stood on its own until it was integrated into Star Trek: Phoenix-X in August 2014. The story focuses on the crew of the USS Mercedes and their transfer to the USS Blade. It was written in 2004, and is not yet completed.
The fiction was based in action with an attempt to include a wide range of alien species. The story involved the non-canon supernatural tentacle species, the Sleri, in the late 24th century.
Matrox takes over the Ferengi vessel Sekel. Meanwhile, Nex, a Ferengi, tries to lead Sith to someone who can help with his vine problem, turning out to be the Sekel. Matrox admits he brought the vine creature to the Alpha Quadrant.