Sonic is a blue hedgehog who is the mascot for the video game company known as SEGA. He can run faster than the speed of sound. He is good friends with Thomas the Tank Engine and his friends. His arch enemy is Dr. Eggman, also known as Dr. Robotnik. His sidekick is Tails.
- Sonic the Hedgehog met Thomas the Tank Engine in Sonic's Adventures of Thomas and the Magic Railroad where he battled Diesel 10 and P.T. Boomer.
- Sonic is an old friend of Mr. Conductor , as he is the one who gave Sonic the gift of his trademark speed.
- Sonic met Thomas the second time on Sonic and Thomas's Adventures of Galaxy Railway as one of the Emerald Searchers.
- Mighty Morphin Power Rangers (A Sonic Crossover) is the first crossover series to be published.
- STAR WARS Episode I: The Phantom Menace (A Sonic Crossover) is the first crossover film to be published