Slyther (The Dalek Invasion of Earth)

Towards the end of the 22nd century Dalek invasion, the Dalek Supreme Controller used a Slyther to guard the Bedfordshire mines at night, where it killed and ate anything it found.

History
After the Slyther broke through a window into a shack where it attacked a small group of humans consisting of Ian Chesterton, Larry Madison, Wells, and Ashton (killing the last), Ian hit it with a rock, causing it to fall down a pit to its death. (TV: The Dalek Invasion of Earth)