Time Wraiths

The Time-Wraith is a villain in the second season of The Flash. It appears after Barry has travelled back through time to have Eobard Thawne figure out the speed force equasion. Time-Wraiths appear to those who have travelled through time without knowing what they are doing.

History
Barry first encounters it during his travel through the time-tunnel, the wraith angrily flying at him. It later appears in Barry's office in the GCPD, much to the shock of the police officers in the precinct. They fire their guns at the wraith which is not affected by the bullets at all. After seemingly searching the precinct, it leaves.

It later resurfaces at S.T.A.R. Labs. To save themselves from it, Cisco and Caitlin lock themselves up in the cell of Hartley Rathaway. They eventually team up with Hartley who uses his gloves to drive away the wraith. Before it returns, Barry travels back into his time. Although it pursues him down the accellerator, Barry from the past tackles it down and the future-Barry returns to his timeline.

The Wraith then follows Barry into the future and proceeds to age him to death until Barry is saved just in time by Hartley Rathaway, who due to the changes Barry made in the past has reformed and blasts the wraith to dust with his sonic gloves.