This request involves two different, iconic series where the query combines the 1977 Doctor Who story "The Invisible Enemy" and Ninjago: Crystalized Season 15, Episode 6. In the classic Doctor Who serial, the Doctor faces a viral infection while introducing the robot dog K9 to the series. Meanwhile, Ninjago focuses on the ninja becoming fugitives after saving Nya and the rise of the Crystal King. You can find more details in the Wikipedia article for Doctor Who and on the Ninjago Wiki . The Invisible Enemy · Classic Who S15 - TARDIS Guide