Exotic matter plasmids, dubbed darklings by the crew of the USS Titan (after a Syrath creation myth describing the Catalysts of creation hiding in the dark), were an unusual type of dark matter formation discovered by the USS Titan in the Occultus Ora region of the Gum Nebula. They were invisible to the naked eye (of every species on the Titan) and were almost undetectable by even the most advanced sensors, though did effectively block light from other sources - so that when among them space appeared to be completely black. The plasmids were unusual organised for a dark matter phenomenon, forming a massive ring around a neutron star.
The Titan had noticed them by chance due to a weird but consistent spike the lower EM band of the Titan's standard sensor sweeps and subsequently spent weeks studying them, gradually refining its sensor equipment to gain a clearer view of the phenomenon and in the process unveil more and more questions about them. While studying them it was necessary for the Titan to undergo a constant sequence of dance like manoeuvres to avoid the darklings while flying among them. While conducting the study the Titan picked up a distress call from the USS Charon and left the darkling system to investigate. (TTN novel: Sword of Damocles)