- You may be looking for Miles "Tails" Prower from Mobius Prime. You may also be looking for Tails (MxYL) from the Mobius: X Years Later universe.
Tails (future version) is a version of Miles "Tails" Prower from an future universe of Mobius. He was tragically killed along with the Royal Family and others when Robo-Robotnik nuked Mobotropolis. (StH: #75, IYF)