Mind prison

A Rakatan prison was an artifact built by the Rakatan species as a form of imprisonment for criminals who had committed particularly terrible crimes. A prisoner's mind was stripped from his body and locked away within the prison, presumably forever. The only means of escaping the prison was into the body of another who had inadvertently become trapped, although this required the consent of both involved. From the outside, it appeared to be simply a mysterious glowing box with runes carved along the side. For prisoners inside, however, the prison took the form of an infinite expanse of white nothingness, with a small cluster of obelisks and a single bed in the middle. Faint whispering could be heard, possibly the voices of others who had become trapped. It was said that the whiteness would drive beings mad if they let it.

Somehow, the Rodian Lurze acquired one of these prisons and sold it to Motta the Hutt. He hired Revan to serve as courier, with one warning: never to open the box. Lurze did not say what would happen if he did, though, and Revan's curiosity overcame his caution, trapping him in the prison. Two others had also become trapped there in the last month, but they had already gone mad and run off into the white void. Revan met the prison's original occupant, a Rakatan warrior who had been imprisoned for leading a rebellion over 21,000 years ago. After all that time the warrior could not even remember his own name, but still desired to escape, and so challenged Revan to the only contest that would be fair to both and applicable in a world where neither had a physical body: a game of riddles. After stumping the warrior with a math puzzle, his one weakness, Revan was given leave to escape back into his own body. However the box worked, he was unable to activate it again.

Appearances
Star Wars: Knights of the Old Republic