Mark I
The Doctor first comes across K-9 in the adventure The Invisible Enemy. Professor Marius claims to have created the robot dog because weight requirements did not allow him to bring his real dog into space.
The Invisible Enemy
Image of Fendahl
The Sun Makers
Underworld
The Invasion of Time
The Ribos Operation
The Pirate Planet
The Stones of Blood
The Androids of Tara
The Power of Kroll
The Armageddon Factor
Destiny of the Daleks
City of Death
The Creature from the Pit
Nightmare of Eden
The Horns of Nimon
Shada
The Leisure Hive
Meglos
Full Circle
State of Decay
Warriors' Gate
K-9 and Company
The Five Doctors
School Reunion
Journey's End
The Doctor first comes across K-9 in the adventure The Invisible Enemy. Professor Marius claims to have created the robot dog because weight requirements did not allow him to bring his real dog into space.
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