Parnassos was a planet in the Unknown Regions that was once a lush and enjoyable world, at least as portrayed by Con Star Mining Corporation in their advertising and training programs. It had mountains, greenery, and crystal blue oceans. The oceans were so clear that the sandy bottoms were visible. Some valleys were rich in greenery and nature’s bounty.

However, a nuclear disaster at Calliope Station caused a dramatic change in the planet’s environment. The oceans became dark, cold, forbidding, and teeming with hungry beasts. Much of the greenery was turned into a large desert with purple sand. Due to the nuclear disaster, the planet’s oceans continued to rise, acid rain was a common occurrence, and most of the food animals were killed off.