Tails

Miles Prower (Japanese: マイルス パウアー, Hepburn: Mairusu Pauā), better known by his nickname Tails (テイルス, Teirusu), is a fictional character of Sega's Sonic the Hedgehog series. Tails also appears in his own spin-off series, comic books, cartoons, and films. He is the second character to consistently appear by Sonic's side in the series. The name "Miles Prower" is a pun on "miles per hour", a reference to the famed speed of Sonic the Hedgehog. He is a two-tailed fox, hence the nickname.