The Three Doctors (Doctor Who) the Third Doctor (Jon Pertwee) for help when Omega drains their civilisation's power. The serial opened the tenth anniversary year of the series, and features the first three Doctors all appearing in the same serial. This makes it the first "Doctor Who" story in which an earlier incarnation of the Doctor returns to the show. A superluminal signal is sent to Earth, carrying with it an energy blob that seems intent on capturing the Doctor. The homeworld of the Time Lords is also under siege, their power being drained through a black hole. Trapped themselves, and desperate to send help,
The Doctor (Doctor Who) with stasers, weapons capable of suppressing regeneration. In "Death of the Doctor", a serial from spin-off programme "The Sarah Jane Adventures", the Eleventh Doctor flippantly responds to a child that he can regenerate "507" times; writer Russell T. Davies intended this line as a joke. Due to the retroactive creation of a numberless War Doctor and the Tenth Doctor's aborted regeneration in "The Stolen Earth"/"Journey's End", the Eleventh Doctor was the final incarnation in his natural cycle. The Time Lords used a crack in the universe to give him a new cycle consisting of an unknown number of regenerations in