Ceti Alpha Five

In the fictional world of Star Trek, Ceti Alpha Five is the fifth planet in the Ceti Alpha star system, consisting of an Earth-type environment, which was eventually settled in the year 2268 by the legendary ruler Khan Noonien Singh and his small group of fellow genetically-engineered supermen in their search for a new world and life away from Earth to flee punishment and defeat following the Eugenics War.

However, while the system was presumably surveyed and ruled safe by Captain James T. Kirk and his Starship Enterprise just prior to Khan's settlement, the planet was infested with deadly parasitic eels which slowly destroyed the minds of their victims, while likewise the sixth planet of the system exploded only six months afterward, shifting the orbit of Ceti Alpha Five and rendering the planet uninhabitable.