Undertale actually started from a dream that the creator, Toby Fox had. But the dream wasn't about the concept of Undertale, but rather the sister game, Deltarune. Undertale was a test to make sure that Toby would be able to produce a game of a large scale, and much to Toby's surprise, the game blew up and reached 51,124 USD by the end of the the kickstarter. The game came out in 2015 and was a huge success. Undertale was heavily inspired by the game Earthbound. The game was developed across 32 months.