Though K-9 later came to be a staple of Doctor Who culture, his original name was FIDO, standing for Phenomenal Indication Date Observation. The initial idea for the robot companion was to use a small actor inside a costume of a Doberman. Five versions of the robotic pooch have existed: four versions in Doctor Who, which are altered in accordance with technical problems affecting the prop (two were regenerated, essentially, whilst a third returned to Gallifrey with Romana); and a fifth version for the K-9 spinoff, which isnt a part of the BBC. Funnily enough, despite it only airing in 2009, a reboot is reportedly being planned already.
