Mr. Pump is a character who appears in the book Going Postal. He is a golem who is assigned to Moist von Lipwig as an assistant/parole officer to prevent his escape from the postal service. He proves ideal for this task, as golems never stop until their task is completed. As Vetinari explains to Moist, no matter where Moist might run even as far as Fourex, Mr. Pump will chase him 24 hours a day/8 days a week until he is caught, even if it means walking across the ocean floor to get to him (since golem's don't breathe this is not a problem). After Moist's one and only escape attempt ends in failure, he resigns himself to the fact that Mr. Pump will be his constant companion and he begins to warm to him and put him to use.
Like all "younger" Golems (under 3000 years old or so), he has no actual name; he is designated by his function. Mr Pump previously worked in a hole in the dark for two hundred and forty years pumping water because his creators had never told him when to stop. His description then was "Pump 19". He was eventually discovered by other golems, and brought back to surface. He is also a member of the Golem Trust and is currently working to buy his freedom through inhibiting the freedom of others as a parole officer.
To this end, he is still powered by inserting instructions into his skull. He can apparently track anyone's whereabouts through "Karmic Signature".
At the end of Going Postal, Mr. Pump is reassigned to apprehend a Randolph Stippler aka Reacher Gilt, whom Vetinari wanted to impress into government service like he had done with Moist.
Mr. Pump, the Golem parole officer says to Moist, "You Can't Run And You Can't Hide" which is a play on the common saying "You can run but you can't hide" which originated in the 1940s, and is attributed to the American boxer Joe Louis (1914-81), who supposedly said this on the eve of his fight with the light heavyweight champion Billy Conn.
When Moist tries to escape from the Golem, Mr. Pump, he finds that his horse has been "clamped" a reference to the wheel clamping device used in the Roundworld to stop an impounded car from being moved - known as the "Denver Boot."
"Mr. Pump does not sleep. Mr. Pump does not eat. And Mr. Pump, Postmaster General, does not stop." This is a paraphrase of a line from 1999 film The Mummy: "He will never eat, he will never sleep, and he will never stop." It also resonates with 1984 film The Terminator: "That Terminator is out there. It can't be bargained with. It can't be reasoned with. It doesn't feel pity, or remorse, or fear. And it absolutely will not stop, ever, until you are dead!"
Moist says to Vetinari, "I know golems are not allowed to hurt people". Moist is applying Isaac Asimov's first law of robotics to the golem. Asimov's Three Laws of Robotics are:
- A robot may not injure a human being or, through inaction, allow a human being to come to harm.
- A robot must obey orders given it by human beings except where such orders would conflict with the First Law.
- A robot must protect its own existence as long as such protection does not conflict with the First or Second Law.
Pratchett pokes fun at these laws when he has Vetinari order Mr. Pump to break one of Moist's fingers and Mr. Pump quotes an addendum to the law "Unless Ordered To Do So By Duly Constituted Authority", which is not part of Asimov's original three laws. This extra addendum continues a common Pratchett theme of subordinates unquestioningly carrying out the orders of a superior, an argument which was at the core of the Nuremburg Trials after WW II and is known as "the superior orders plea" or the "Nuremburg Defense".