Blastoneuron

Neural parasites were a dangerous form of undetermined origin. They were roughly disc shaped, an anatomically resembled a single large brain cell. They were capable of individual flight, but most commonly attached themselves to humanoid hosts, via a "stinger" which tapped into the spinal cord. This allowed control over the host, though it also caused severe pain, and madness.

These parasites were believed to have traveled from the Beta Portolan system to Levinius V, then Theta Cygni XII, and in 2265, Ingraham B. By 2267 they had reached Deneva, where they were encountered by the crew of the USS Enterprise (NCC-1701). The crew of that ship discovered the parasites were vulnerable to visible light, and were able to eradicate them by placing a series of UV light-producing satellites in Denevan orbit.