Timeline C

Timeline C is a hypothetical timeline that may or may not exist, depending on unconfirmed events. It is possible that, at the end of Rat Movie 2: The Movie and the recorded events of Timeline B, the Cats became enraged after Giant Rat #9,376 destroyed the Noah's Ark Toothbrush, by throwing it into the "fires" of "Mount Doom". Theoretically, they would then turn back time again, just as they did at the end of Timeline A, resulting in a new timeline and, presumably, Rat Movie 3.

However, given that Rat Movie 3 does not yet exist, the prevailing theory is that the Cats, using their vast intelligence, realized that turning back time again would simply put them into an endless loop of war and torment, watching helplessly as rats destroy their precious toothbrush again and again. Thus, they decide to admit defeat, and move on to other areas of intergalactic conquest.

Overall, it is difficult to say whether or not Timeline C actually exists, as some believe the Cats are too stubborn to relent in their efforts to claim the toothbrush, while others believe they are too intelligent to walk right into a stable time loop. There has been much debate over this issue, probably. Out there, somewhere. I'm sure of it.

Trivia
In Timeline C, the lyrics to The Birthday Song are "Celebrating yet another birthday bash".