Sky-Sheep
From Tardis Wiki, the free Doctor Who reference
The planet of the Sky-Sheep was visited by the the Eleventh Doctor and Amy. They were there when the Space-Wolves arrived with guns and attacked these rainbow-coloured sheep with spindly legs, and the story of their adventure proved thrilling enough to entertain the story-hungry Book Monster’s that the Doctor encountered when returning his overdue library books. (DWAM: Booked Up)