Scorby

Scorby was a ruthless mercenary in the employ of Harrison Chase.

On Chase's orders, Scorby and Arnold Keeler travelled to a scientific base in Antarctica. There, he stole a Krynoid pod which had been discovered, destroyed the base with a bomb, and brought the pod to Chase Mansion in England.

Scorby took the Fourth Doctor and Sarah Jane Smith prisoner when they arrived at Chase Mansion. They escaped and Scorby attempted to recapture them. He caught the Doctor and planned to put him through Chase's compost machine. The Doctor was rescued by Sarah Jane.

Scorby later turned against Chase after seeing how dangerous the Krynoid was. While trapped in a cottage alongside the Doctor, Scorby used a molotov cocktail to distract the Krynoid, allowing the Doctor to escape. He later hid within Chase Mansion and helped defend it from the Krynoid's attack. Disbelieving in the Doctor's ability to deal with the problem, he tried to flee by wading across a pond, but was drowned by plants controlled by the Krynoid. (TV: The Seeds of Doom)

Behind the scenes
The scene in which the Doctor and Sarah Jane escape from Scorby in part three is notable (and often cited) for its violence, with the Doctor appearing to snap the man's neck, though this isn't the case and Scorby recovers and chases after them.