Dr. Skagra is the main antagonist in the Doctor Who serial, Shada.
Skagra learned of a Time Lord criminal called Salyavin who was imprisoned on a prison planet called Shada because he had abused his powers which were to put his mind into other people and effectively control them. Skagra wanted Salyavin's mind and to do this he devised a sphere that could drain the minds of anyone and implement all of their knowledge into Skagra's mind. If Skagra could drain Salyavin's mind then he would have Salyavin's power and he could then make the entire universe function as one god-like entity; Skagra's mind.
First, Skagra required an ancient Time Lord book that was the key to unlocking Shada. Eventually, Skagra learned how to do this while stealing the Doctor's TARDIS and holding Romana hostage. At Shada, Skagra discovered nothing but a dummy in Salyavin's cell. The Doctor's Time Lord friend, Professor Chronotis, revealed himself as Salyavin. Chronotis wished to forget what he had done in the past so he stole the ancient book from Gallifrey and made the Time Lords lose all knowledge about Shada, thus allowing Salyavin to adopt a new name and settle on Earth. Skagra drained the Professor's mind immediately and began his mind revolution with the prisoners of Shada functioning with him.
Before Skagra and the prisoners could invade the universe, the Doctor emerged with a device atop his head which allowed him to lock his mind with Skagra and confuse the prisoners. The Doctor and Skagra then mind battled each other. Skagra was gaining the upper hand but Romana was able to destroy Skagra's creations, the Krargs, which caught Skagra off balance and allowed the Doctor to turn the tables on him. Skagra retreated to one of his ships in the docking bay. However, his talking ship held him prisoner in the brig because the Doctor had earlier tampered with the ship's circuitry. Skagra was then imprisoned by his own creation, unable to persuade it otherwise.