The Universe Is Toast (often abbreviated as TUIT) refers to the title of the expected, but unproduced trilogy following Keen 6. In it, Keen was supposed to prevent the destruction of the entire universe, taking on his old arch-nemesis Mortimer McMire. Sadly, id Software decided that they had more productive projects to work on and the series remains merely a suggestion to this day.
There remains some support for the series, however, mainly in the form of two of the original id team, John Romero and Tom Hall. Tom especially has often expressed his desire to personally contribute to TUIT, most likely as a 3D platformer game. As yet, the only remaining obstacle to its production is the refusal of id Software to release the intellectual property rights back to its creator.
Source KeenWiki