PLANET OF ORIGIN: Asteroid K4067
DOCTOR(S): Fourth, Tenth
This is slightly a cheat, given that four different K9s have appeared on Doctor Who (not including the Australian co-produced 2010 series, K9). But they’re all much the same, being robotic dogs with an aversion to linguistic contractions and an ability to insert a surprising amount of sass into pedantic pronouncements. Originally created by a human scientist living off-world, all versions of K9 have been brave, intelligent (yes, he’s a computer, but he can also beat the Doctor at chess) and loyal. But more towards the companions than the Doctor (versions of K9 leave the Doctor in order to stay with Leela and Romana, not to mention Sarah Jane’s K9 Mark III).
PLANET OF ORIGIN: Gelsandor
Kamelion is counted as an official companion by the BBC, but you’d be hard pressed to find any other companion who the Doctor attempts to lose inside the infinite walls of the TARDIS. With the ability to project any person onto his shell, and with a worrying tendency to be psychically dominated, Kamelion first encounters the Doctor while he’s pretending to be King John under the influence of the Master. After being freed from the Master’s control and entering the TARDIS, Kamelion completely vanishes for the next five stories, until the TARDIS lands on Lanzarote and the Master starts controlling him again. As a prop, a bit unusable. As a character, a bit absent.
According to cast and crew, neither was particularly fun to work with.
But which worked better on the show?
Let us know in the comments below!