Before the UrSkeks split, it was the Scientist who gave Aughra the most help in building her observatory. SkekTek's alter ego amongst the good hearted Mystics is urTih the Alchemist.
SkekTek later met his death when the animals in his laboratory retaliated with the help of Kira, pushing him into the shaft of the Dark Crystal, where he fell to his death. Sadly, this death also killed urTih.
Steve Whitmire later used a voice similar to the SkekTek's for Marlon Fraggle.
In pre-production notes for the film, skekTek, who was also called the Doctor, is "identified by his self-mutilated body, especially an artificial leg and bionic arm. His pale, pink-white neck is held in place by a brace with metal bits, and his body is fed through chrome and plastic tubes. One eye is fitted with a telescopic eyepiece."
"To betray is to break the circle of trust. The Skeksis came to betray all friendship, without reason, without need. The end of my friendship with skekTek the Scientist is still bitter. Before the division, TekTih of all urSkeks gave me most; then his divided soul became Alchemist and Scientist alike. When the urSkeks first came to the World he taught (Aughra) all the movements of the skies and designed the great Observatory. And in return (she) gave him all (her) knowledge of the rocks, even to the secrets of the metals.
SkekTek kept some real power of thought, but in truth he had become only a juggler of ideas, of memories from his previous life. Then he had studied the light of the Crystal and used it for the division; now he studied the wounded Crystal, and by that light he saw his ways to acts of darkness. Two great evils I charge against him. First, that he learned the art to make beams of light from the Dark Crystal, which he burned into Pod People's eyes to make them living ghosts, his perfect slaves. After the light had struck them no light lived in their eyes, but they obeyed; that was all.
And the second worse evil was to use dark light to draw the essence of life, to drain it from the living to make a drink for the Skeksis, above all for the Emperor. This essence gave them back their youth and vigor for a while, only for a little; but many Gelflings were victims forever."
SkekTek was one of the cruelest of the Skeksis. He had amputated his own right arm and right leg and replaced them with mechanical ones (however his original right hand was reattached to his metal arm). His missing right eye was replaced with a glowing bionic one.
It was his job to extract life essence from captured Gelflings, and later Podlings in his laboratory, the Chamber of Life. When the Chamberlain captured Kira, the Scientist took her into the Chamber of Life where he prepared to drain her essence - as Gelfling essence was more potent than Podling.
At the urging of Aughra, held captive there, Kira use her ability to communicate with wildlife to summon the help of the hundreds of animals the Scientist kept caged in his lab. Swarmed and attacked by the animals, the Scientist stumbled backwards and fell through the opening in the chamber wall, and down the fiery shaft to his death. His demise resulted in the simultaneous death of his Mystic counterpart, the Alchemist. Had both lived to see the Great Conjunction, they would have combined to create the UrSkek TekTih.
- His death is different in A.C.H. Smith's novelization and the comic book; in the former he falls through the door to the shaft lunging at Aughra in an attempt to kill her, and in the latter he falls into a random, flaming pit instead of the castle shaft.
- In the novel and comic he does not have a bionic eye.