Hösndösn is a planet in an unknown location. Mario unintentionally travels to this planet in the Club Nintendo comic "Super Mario: Verloren in der Zeit". He is taken there by a malfunctioning time machine. The only known inhabitants of Hösndösn are the aliens Hösn and Dösn, who seem to be responsible for organizing an event called the "intergalactical Olympics" (which is very similar to the Winter Olympics on Earth), and Klösn, who obviously is a human and is involved in the Olympics as well. As the story takes place in the future, some futuristic buildings and flying objects are found on Hösndösn. During the Olympics, some video game characters can be seen on the planet, such as the sportsman Plok and the Star Fox characters Fox McCloud, Falco Lombardi, and Peppy Hare in the audience. Hösndösn has several moons, one of which is extremely large. The terrain overall appears to be rocky and barren.
Various aspects suggest that Hösndösn is very similar to Earth or the Mushroom World. Not only do several humans live on Hösndösn, but there is also an Olympics and even the language is not much different to Mario's. The inhabitants, however, replace the vowel "o" with the umlaut "ö" (hence the name of the planet) on certain occasions.