Nazo

Nazo, also known as Nazo the Hedgehog and Nazo the Negative, and also calls himself the "Ultimate Life Form", was a villain who was going to appear in Sonic X but was cut. Nazo only appeared in the pilot episode for a split second. Nazo also appears in the popular fan work Sonic: Nazo Unleashed (which takes place between Shadow the Hedgehog and Sonic Unleashed) as the main villain. Nazo Unleashed was not officially created by SEGA, but is widely renowned, was acknowledged by them, and Sonic's former voice actor Ryan Drummond stated that he thought it was expertly done.Nazo also appears in the semi-official sequel Sonic: The Return of Nazo, though an official sequel is being planned.