Second Doctor
The Second Doctor is an incarnation of the Doctor, the protagonist of the BBC science fiction television series "Doctor Who". He was portrayed by character actor Patrick Troughton.
Eighth Doctor
The character was introduced in the 1996 TV film "Doctor Who", a back-door pilot produced in an unsuccessful attempt to relaunch the series following its 1989 cancellation. While the Eighth Doctor initially had only one on-screen appearance, his adventures were portrayed extensively in subsequent spin-off media, including more than 70 audio dramas starring McGann. In 2013, the actor reprised the role in the mini-episode "The Night of the Doctor", which depicts the Eighth Doctor's final adventure and his regeneration into the War Doctor (played by John Hurt).