The robot dog named K9 was featured in the famous TV series "Doctor Who." K9 first appeared in the long-running British science fiction series in 1977 during the Fourth Doctor's era, played by Tom Baker. K9 is a robotic dog companion to the Doctor, equipped with various advanced capabilities, including intelligence, laser weaponry, and the ability to traverse time and space. The character K9 became popular among fans and has made several appearances throughout the history of "Doctor Who," often assisting the Doctor in their adventures.