Proto was a planet located in the galaxy's Alpha or Beta Quadrants on the outskirts of Federation-explored space in the 23rd century.
History and specifics[]
Proto orbited 457 million miles from its primary, a rare green star. While apparently far outside the system's habitable zone, sensors claimed it had Earth-comparable gravity and atmosphere. It appeared to have several green-colored continents and oceans when seen from space.
In the year 2285, the science vessel USS Surak visited Proto to conduct a planetary survey. When a landing party beamed down, however, the team members immediately fell into a deep sleep, dreaming vividly, and were unable to be revived after being retrieved. Captain Spock eventually managed to will himself awake, then aided the rest of the team with a mind meld.
Following the experience, Spock recommended that the planet be declared off limits as a hostile world, then Surak set course for Starbase 12. (TOS comic: "Dreamworld")