Moon

Moon is a lifeless airless low-gravity world with a lot of Crystal Erchius Fuel and Liquid Erchius Fuel.

If you carry any Erchius in your inventory, you will be chased by Erchius Ghost (it becomes faster as you mine more fuel). You can avoid this by equipping Erchius Buddy.

If such planets creep you out, you can instead visit Rocky Moon, Desert Moon, Toxic Moon, Frozen Moon or Volcanic Moon. They don't have Erchius Ghost, but they have other monsters. Even creepier Shadow Moon has both Lighless Erchius Ghost and other monsters.