Miles "Tails" Prower

Miles "Tails" Prower is Sonic's sidekick in the Sonic Series. He's a two tailed fox who can use his tails to fly. The character was created by Yasushi Yamaguchi during an internal contest held at Sega to design a sidekick for Sonic. Yamaguchi originally conceived the character with the name "Miles Prower", however the rest of the creative team where not keen on the idea, and they instead went with the suggested name of "Tails".

Sonic the Hedgehog 2 (8-bit game)
Tails made his debute in Sonic the Hedgehog 2. Tails, like most of Sonic's animal friends has been kidnapped by Dr. Robotnik, but managed to leave a note for Sonic informing him where they where being held, a place called Crystal Egg. Robotnik is holding them ransom for six chaos emeralds, and Sonic must journey to collect them if he hopes to see his friend again.

Sonic the Hedgehog 2 (16-bit game)
Sonic provided the emeralds to Robotnik only to discover the Doctor plans to use them to power his Death Egg space station, thus both Sonic, and Tails set off to stop his evil plans. Tails follows Sonic where ever he goes on this jounrney, and his ability to fly is an asset.

Sonic the Hedgehog (Saturdaymorning Cartoon)
Tails is a fox raised by birds whom Sonic takes under his wing.