Revealing mistake: While the Doctor and Clara visit the market in Akhaten, the rubber mask of one of the aliens they encounter is revealed, as the eyes of the actor wearing it are very much visible. (00:08:10)
Continuity mistake: After the Doctor gets hit in the head by a football, when he raises his arms defensively when Ellie Oswald comes over to see if he's all right, his arms switch positions between the wide shot and the close-up. (00:02:02)
Continuity mistake: The leaf Clara feeds the Old God, which was the catalyst for her parents meeting and which she kept tucked in her book as "page 1", looks completely different to its first appearance in "The Bells of Saint John".
Chosen answer: No, no information is avalible for the identity of the entity.
Repo_Man