Kamelion

Kamelion was a shape-changing android and the companion to the Doctor.

Creation
Kamelion was the creation of Gelsandorans. (PDA: The Ultimate Treasure) Kamelion was the tool of an invader of the planet Xeriphas. When the Master was trapped on that planet, he discovered Kamelion and used him in his next encounter with the Doctor. Although Kamelion was sentient to a degree, it was also extremely weak-willed, and therefore open to manipulation by any strong personalities around it. (DW: The King's Demons)

Travels with the Doctor
The Doctor freed Kamelion from the Master's grip, and it joined the Doctor in the TARDIS. (DW: The King's Demons)

Kamelion preferred to remain in the TARDIS for fear of being taken over by a stronger personality and used against the Doctor. (MA: The Crystal Bucephalus)

Kamelion eventually fell under the Master's remote influence in Lanzarote and assumed the shape of Peri's loathed stepfather Howard Foster and then the Master himself. In the end, Kamelion begged the Doctor to end its life. The Doctor reluctantly honoured that request. (DW: Planet of Fire)

Afterlife
A little of Kamelion's personality survived as a result of its interfacing with the TARDIS. When the ship arrived on Gelsandor, the natives gave it a new body, only for it to sacrifice itself to save the Doctor and Peri. (PDA: The Ultimate Treasure)

Later, Kamelion and the TARDIS had a child together, which was raised by the Doctor and Peri. It developed into a double of Peri and took her place on Earth while the real Peri travelled with the Doctor. (ST: The Reproductive Cycle)

Other information

 * Kamelion assumed the shapes of John of England, Tegan Jovanka (DW: The King's Demons), Howard Foster and the Master. (DW: Planet of Fire)


 * While dying for the effects of Spectrox toxaemia, the Doctor hallucinated Kamelion urging him to live. (DW: The Caves of Androzani)

Behind the Scenes
Kamelion only appeared twice in the series; further appearances were made impractical by the special effects required. A scene involving Kamelion was filmed for The Awakening but was cut before transmission. As a result there are no references to Kamelion in any episodes between The King's Demons and Planet of Fire, not even in The Five Doctors.