Light (Ghost Light)

Light was a member of an alien species, he traveled through the universe making a catalogue of life

Biography
Light was a traveller of the universe, he took it upon himself to create a catalogue of all organic matter. He took Nimrod, a member of the Neanderthal race as a specimen for his catalog. Redvers Fenn-Cooper claimed to have seen a dazzling light while hunting in Africa; he said it had wings and other features similar to that of Light. Light had been asleep for centuries while in his spaceship and while he had, life had been evolving. Josiah Samuel Smith was Light's survey run under the auspices of another alien on Light's ship, Control. Josiah changed to mimic the different life on earth and in doing so leaves behind Husks. Light's form depended on his environment, and so when he awakes he appeared as a Human in an alien robe who glowed with a yellow light. The Doctor explained to Ace that he moved at the speed of thought. Accordingly, he had the power to teleport.

Light was a most confusing entity: his appearance was majestic and imposing, which wildly contrasted with his bewildered, frustrated behaviour, doddering speech pattern and screeching timbre.

Light was angry that his catalogue was ruined due to life evolving and so he decided to destroy all organic matter so that it would stop changing and his catalog would be complete. He killed a maid and took her apart in order to see how her body worked. He killed Inspector Mackenzie and turned him into soup and also turned Lady Pritchard and her daughter Gwendoline to stone. The Doctor showed Light that he himself was evolving and, realising that he was wrong, dispersed. (DW: Ghost Light)