Pluto is a dwarf planet located in Earth's solar system. inhabited by sentient Plutonians. The planet is first mentioned in Something Ricked This Way Comes, when Jerry and Morty Smith are abducted and transported there.
Pluto is ruled by King Flippy Nips, a denier of Pluto's environmental shrinking crisis and close associate of Pluto's corporate leaders. His son, Scroopy Noopers, is an activist who aims to stop the mining operations responsible for Pluto's shrinking.
The appearance of Pluto is immensely dull with little-to-no details. The ground is mainly blue and the buildings are mushroom shaped.
Pluto first appeared in Something Ricked This Way Comes, when Morty and his father Jerry were making a model of the solar system as a science project for school. When Jerry started to add Pluto to the model, Morty pointed out to him that Pluto was "no longer a planet." He then Googled it and confirmed that the celestial body is, in fact, no longer considered a planet, due to several other bodies in the solar system being larger and/or having more planetary mass than Pluto. Jerry, outraged at this change from the science he grew up with, called NASA to chew them out about Pluto, claiming that it is still a planet.
Unbeknownst to the Smiths, the Plutonians were monitoring Jerry's phone call, and decided to abduct him and Morty so the two could serve as representatives of Earth's science, and convince the Plutonians once and for all that Pluto is a planet.
After Jerry makes several public appearances to the Plutonians, claiming that Pluto is still a planet, Morty is taken aside by the environmental activist Scroopy Noopers, who shows Morty that the dwarf planet is shrinking due to mass mining of Pluto's resources; namely, plutonium. Noopers explains that if the mining continues, Pluto will continue to shrink until it "poofs" out of existence. Morty reveals this fact to Jerry, who finally folds and announces to the population of Pluto that it is no longer classifiable as a planet, enraging them and resulting in him and Morty being returned to Earth.
The future of the planet is unknown, but it is likely that the dwarf planet will continue to shrink until it is destroyed, or until the seismic activity caused by the mining of plutonium destroys all life on the planet, as well as the mining facilities.
One major industry on Pluto is mining for plutonium to power cities.
Due to excessive drilling by Plutonian corporations, Pluto shrunk and led Earth's astronomers to reclassify it as a dwarf planet rather than a planet. This decision angered the local population and is actively fought against by the Plutonian elite.