Miles Prower マイルス・パウアー , better known by his alias Tails テイルス The name "Miles Prower" is a pun on "miles per hour," a reference to the famed speed of the Sonic the Hedgehog series. He is an eight year-old,anthropomorphic, and humanoid yellow fox with two tails, hence the nickname. He is known to be Sonic's sidekick and a mechanic. He is able to use his two tails to propel himself into the air like a helicopter for a limited time

Info:supported by Wiki

SEGA (c) Created by Yasushi Yamaguchi
Designed by Yasushi Yamaguchi (Sonic the Hedgehog 2)
Yuji Uekawa (Sonic Adventure)