Time Blank
From Tardis Wiki, the free Doctor Who reference
Time Blanks were beings which partially existed outside of normal time. They were capable of manipulating time, allowing them to slow it down, stop it, or speed it up. However, they were only capable of sustaining their existence in normal time by absorbing the life force of another. Taphony was a Time Blank created by the Department as part of their time travel experiments. (K9TV: Taphony and the Time Loop)