Shadow the Hedgehog (シャドウ・ザ・ヘッジホッグ, Shadō za Hejjihoggu?) is a character that appears in the anime series Sonic X and its comic series published by Archie Comics. He is a dark doppelgänger hedgehog and the arch-rival of Sonic the Hedgehog. Shadow was created by Gerald Robotnik, and is the end result of Project Shadow. However, the project was closed, and Shadow was captured by G.U.N. and put into stasis on Prison Island after his friend Maria Robotnik was killed.

Fifty years later, Shadow was awakened from hibernation by Gerald's grandson, Dr. Eggman. Initially, Shadow's goal was to destroy the Earth and avenge Maria's death, but he ultimately decided to save humanity, which almost cost him his life. The black hedgehog later returned to save the universe from destruction. Again, he joins forces with Eggman and Rouge the Bat during the galactic war with the Metarex.