From ImperialWikione-episode energy cloud race from the TOS episode "Is There in Truth No Beauty?"
- "While the thoughts of the Medusans are the most sublime in the galaxy, their physical appearance is exactly the opposite. They have evolved into a race of beings who are formless, so utterly hideous that the sight of a Medusan brings total madness to any human who sees one."
- -- Captain's Log
Alien of the Week Features
- The Medusan form is incomprehensible to humanoids: a person who sees a Medusan will go insane, becoming dangerous to his or her self and others.
- Vulcans can tolerate the appearance of Medusans if they look through a special filter, but without the filter, they too will go mad from the sight.
- When interacting with humanoids, Medusans occupy opaque travel pods with sensors and communications gear to protect their associates.
- Medusans are highly intelligent.
- Medusans are telepathic, but such contact is limited to communication with other telepaths.
- Medusans have an innate sense of their location in time and space that makes them intuitive navigators.