K2 was an Experimental Prototype Robot, based on the original K1 to the point of sharing its appearance and memories. It was created by the Unified Intelligence Taskforce in an experiment with living metal on the orders of the British government, UNIT having been given the formula for living metal with express instructions to keep it safe. They had believed that human technology had advanced to the point where they would be able to control the technology.
K2 began growing at an alarming rate and escaped into downtown London where it went on a rampage. Osgood quickly phoned the Twelfth Doctor; who saved her from being stepped on by K2. He materialised his TARDIS near K2 and used his sonic screwdriver to dismantle it. Unfortunately, the Doctor had arrived a few moments too late and was unable to prevent K2 from destroying a famous London landmark: the London Eye. (COMIC: Robo Rampage)