As the name suggests, the chili dog is a generic name for a jumbo frank served in a bun and topped with some sort of meat sauce with chopped onions and a spicy substance known as chili.
Sonic the Hedgehog
After starting a bar fight in the Piston Pit, Sonic discovered a platter with six chili dogs while running around at super speed, and ate them all. However, they would end up giving Sonic a case of flatulence.
Around the World in 80 Seconds
When he visited New York City, Sonic tried out a chili dog there, though he noted that it "did not have enough chili".
- Sonic the Hedgehog's fondness for chili dogs is something that originates in western territories, first established in the Adventures of Sonic the Hedgehog television series. Even before that, the earliest canon reference to Sonic's enjoyment of hot dogs (rather than the more specific chili dogs) was in Sonic the Comic #5, where Sonic is having three hundred hot dogs as a part of his breakfast. In the years since, the chili dog has been established as Sonic's favorite food in just about every Sonic-related media, eventually making its way into the games' canon as well.