Deltarune
After previously teasing something Undertale-related a day earlier on Twitter, Fox released the first chapter of Deltarune, a game "intended for people who have completed Undertale", on October 31, 2018 for Windows and macOS for free. Fox said that this release is the first part of a new project, and considered the release a "survey program" to determine how to take the project further. Fox mentioned that Deltarune will be a larger project than Undertale. He will release it as one game (not chapters) after forming a team to develop it. Fox plans for Deltarune to have only one ending.