"Unknown from M.E." is the theme song of Knuckles the Echidna from Sonic Adventure and Sonic Adventure 2. It was performed by Marlon Saunders with Dred Foxx in Sonic Adventure, and by Marlon Saunders and Hunnid-P in Sonic Adventure 2. It was also featured in Sonic and the Black Knight as Sir Gawain's theme and could be played when the Medal of Gawain is used.