Crooked Man (Hide)

The Crooked Man was a peculiarly-shaped creature of an arachnid-like species that happened to be trapped in a pocket universe.

At some point, the Crooked Man became separated from his mate. He began chasing Hila Tacorien in the pocket universe, but the Eleventh Doctor, with the assistance of Emma Grayling, found her and took her to an echo of Caliburn House. The Doctor shut the Crooked Man behind a door in one of the echo house's rooms, but as Hila Tacorien was pulled to N-Space, the wormhole connecting the pocket universe to N-Space failed, and the Doctor was left behind.

The Crooked Man pursued the Doctor and knocked him over, but Clara Oswald rescued him in the TARDIS. Realising the mistake he made as to the nature of the creature, the Doctor returned to the pocket universe, again through Grayling's psychic powers, so that Clara could pick the Crooked Man up in the TARDIS and return him to his mate. (TV: Hide)

Behind the scenes
This individual was never named during the episode itself, but was described as The Crooked Man in the end credits. He was named "the hider" by Doctor Who Adventures.