K-9 is a Doctor Who gadget in LEGO Dimensions . He is The Doctor's personal gadget, and is included in 71204 Level Pack.
K-9 Mk1 was a robot dog built by Professor Marius in the year 5000. He was given to the Fourth Doctor and travelled with him and his companion, Leela. When Leela decided to stay on Gallifrey following a Sontaran invasion, K-9 decided to stay with her. Following this, The Doctor built a new and improved K-9 Mk2, which later stayed with The Doctor's companion, Romana. The Doctor built a third K-9 as a present for his former companion, Sarah Jane and the two had a number of adventures. This K-9 sacrificed himself to stop a Krillitane invasion, and The Doctor built Sarah Jane a fourth K-9. This K-9 has helped Sarah Jane and her friends defeat many alien invasions.
In LEGO Dimensions, the Twelfth Doctor uses an unspecified K-9 unit that can be converted in the K-9 Ruff Rover and the K-9 Laser Cutter.