The Grey is an endless route lacking color that is found in all known areas through the use of glitches, hacks, or exploits, and is considered one of Toontown's greatest mysteries. Toons that somehow make their way into the Grey can travel forever and never find anything. In some cases, Toons enter the Grey unintentionally or to ensure that a difficult task is done properly without failure.
- In Toontown Online, a few sections of streets had fences that could be walked through.
- Slappy once mentioned that the Grey is one of the many things that bewilders him and wonders what secrets it holds.
- On the Toontown Rewritten website, Professor Prepostera made a blog post about the Grey, describing it as an unnatural place and an outstanding creative approach, yet pesky way to bypass security in Cog facilities. He also made a previous blog post introducing his research project about the Grey.
- In a Q&A livestream hosted by Slate on March 24, 2014, Sir Max confirmed that the Grey is canon to the storyline.
- If a Toon jumps while traveling in the Grey, they will jump and then hover in mid-air in a jumping pose until they come into contact with a surface again.
- The sky or background related to the respective area from where the Toon is located can still be seen in the Grey.