Corvid

The Corvids were a race of vampire-like scavengers that lived in the Time Vortex and usually fed on the psychic essence of the deceased. When they began attacking the living, they gained an impossible to sate taste for their psychic energy, but had been bound to Highgate Cemetery and were unable to escape. In 1972, the Corvids killed Dave, and also attacked a cult led by Gabriel Rosewood, who had been seeking the power of the "Highgate Vampire". They killed Rosewood as well and tried feeding on Clara Oswald, but found her toxic due to her unique connection to the Vortex where she once splintered into a million Claras. The Twelfth Doctor then used the ley lines the cemetery was built on to banish the Corvids back to the Vortex. (COMIC: The Highgate Horror)

Six months later, Jess Collins told off the Doctor for running off in the TARDIS after Rosewood tried to kill them and having suddenly come back. The Doctor recalled preventing Rosewood from unleashing the Corvids and nearly killing the Doctor and Jess, but not Clara being present, (COMIC: The Pestilent Heart) due to the Doctor's memory of Clara being wiped by a neural block. (TV: Hell Bent)