The Underwhere is a location in Super Paper Mario. It is also called World -1 by one of the residents, a reference to the famous "Minus World" glitch from the original Super Mario Bros.. Ruled by Queen Jaydes, The Underwhere makes up one half of the "afterlife" dimension, and is where people who have been neither good nor bad from "all worlds" go when they die. Once there, the people become what are known as Shaydes (a corruption of the word "Shades"). They often chat about how they got a Game Over (such as being hit in mid-jump by a Micro-Goomba and falling into a bottomless pit). According to The InterNed, the music of the Underwhere goes by the same name: "The Underwhere".
As the Underwhere is not a place of suffering and pain, just boredom and dullness, it should be compared to the Asphodel Meadows of the ancient Greek underworld, rather than the multi-regional Hell. Queen Jaydes herself was named for the Greek god of the underworld, Hades, and there are numerous other aspects of The Underwhere taken from Greek mythology (listed below). However, the Underwhere's counterpart, The Overthere, where the sinless can spend eternity as angelic Nimbis, is more heavily based on Heaven than the Greek Elysian Fields. Bonechill's prison, the place where people go when they have been very bad in life, is equivalent to Tartarus, also from Greek mythology, although the fact that he was a fallen Nimbi and his association with ice does bear resemblance to the story of Lucifer, who, according to Dante's Inferno, is trapped in ice in the deepest circle of Hell.
The Underwhere also contains a special fountain that restores Mario and Co.'s HP.
 Super Paper Mario
In Super Paper Mario, Mario, Princess Peach, and Bowser are teleported "to the next world" by Dimentio. The game acknowledges this as Chapter 7, and the beginning of The Underwhere is Chapter 7-1. It is here that Luigi loses his identity as Mr. L and joins Mario's party.
Throughout the beginning of the chapter, only Mario and Luigi may be used to open the Purple Door. Tippi, the Pixls that Mario gathered, Peach, and Bowser are all unavailable at the start (as is Luigi, until Mario finds him). Tippi and the Pixls become available at the end of Chapter 7-1 (when Mario and Luigi receive the then-revitalized Pure Heart from Sammer's Kingdom and return to Flipside). Neither Bowser nor Peach are found until Mario's trek through the Underwhere Road and the Overthere Stair, respectively.
 Areas in Chapter 7
 References made in the Underwhere
In the Underwhere and its counterpart, the Overthere, many characters or places that are encountered are references to other things, in most cases the names are specifically based off of Greek Mythology.
 Names in Other Languages