Pac-Man World Rally was originally going to be based on the works of famed psychedelic hot rod cartoonist Stanley Mouse. Fygar's kart is a leftover from this version of the project, hence why it doesn't fit the aesthetic style of the other karts and isn't directly based on the Dig Dug franchise

Inside the prototype Xbox version of Pac-Man World Rally, files pertaining to Snoopy from Peanuts and a vehicle for him can be found. While the initial discovery of these files left a lot of mystery over whether they were leftovers from another project or a scrapped crossover, a concept image from World Rally would emerge shortly after revealing Snoopy was indeed planned as a crossover racer.

Smart Bomb Interactive, the developers of Pac-Man World Rally, worked on the game Snoopy vs. the Red Baron around the same time, and a few shared files from that game including placeholder cutscene dialogue can also be found in Pac-Man World Rally's data.