- "Colin! The Security Robot called Colin!"
- —Colin the Security Robot on being given his new name
Colin the Security Robot was a unit employed by Infinidim Enterprises. He was found by Ford Prefect, who subsequently named him Colin after a dog of a person he knew called Emily Saunders. Colin is an over-excitable, over-joyed and very annoying floating robot. He met Ford Prefect while Ford was climbing up a lift shaft. He threatened Ford to show his long list of expenses but after being reprogrammed, told Ford how to wipe them off the system. He saved Ford's life after he was forced to jump out a window of the Hitchhiker's offices by flying under Ford's towel and pulling him onto a window sill.