One of the truly frequently asked questions on alt.fan.pratchett is “Where does this phrase come from?” (Foul Ole Ron also uses it, in Soul Music.)
The answer concerns Terry’s experiments with computer-generated texts:
“It was a program called Babble, or something similar. I put in all kinds of stuff, including the menu of the Dragon House Chinese take-away because it was lying on my desk. The program attempted to make ‘coherent’ phrases (!) out of it all.”
One of the other things Terry must have fed it were the lyrics to the song ‘Particle Man’ by They Might Be Giants:
Universe man, universe man
Size of the entire universe man
Usually kind to smaller men, universe man
He’s got a watch with a minute hand
A millennium hand, and an eon hand
When they meet it’s happyland
Powerful man, universe man.