Medusan
- Appearance: Noncorporeal
- Physical appearance is capable of driving most humanoids crazy due to noncorporeal nature (TOS: "Is There in Truth No Beauty?")
- Biological notes
- Telepathic species (TOS: "Is There in Truth No Beauty?")
- Innately aware of position in space and time at all times, granting them innate skill at starship navigation (TOS: "Is There in Truth No Beauty?"; TNG Novel: A Time to Be Born)