Nuon City

"Nuon City" was a city on Cybertron that Underbite apparently ate.

History
In Pilot (Part 1), Underbite mentions to Sideswipe that the reason Nuon City was never heard from is because Underbite had devoured the whole city.

In Brainpower, Simacore mentions Nuon City in a question that he gives Grimlock, who immediately remembers and explains that Underbite had devoured the city making Simacore's question out of date.