"The mice were furious."
[...]
"Oh yes," said the old man mildly.
"Yes well so I expect were the dogs and cats and duckbilled platypuses, but..."
"Ah, but they hadn't paid for it you see, had they?"
"Look," said Arthur, "would it save you a lot of time if I just gave up and went mad now?"
[...]
"Earthman, the planet you lived on was commissioned, paid for, and run by mice. It was destroyed five minutes before the completion of the purpose for which it was built, and we've got to build another one."
Only one word registered with Arthur.
"Mice?" he said.
"Indeed Earthman."
"Look, sorry - are we talking about the little white furry things with the cheese fixation and women standing on tables screaming in early sixties sit coms?"
Slartibartfast coughed politely.
"[...] These creatures you call mice, you see, they are not quite as they appear. They are merely the protrusion into our dimension of vast hyperintelligent pandimensional beings. The whole business with the cheese and the squeaking is just a front."
The old man paused, and with a sympathetic frown continued.
"They've been experimenting on you, I'm afraid."

Aye, we played at being mice, forgetting cats are real.

In the real world, mice do exist and they generally go about their business whether we see them or not. (p. 17)

To the extent that we accept this view, we effectively mistake ourselves for highly dimorphic animals such as peacocks or deer.

MOUSE, n. An animal which strews its path with fainting women. As in Rome Christians were thrown to the lions, so centuries earlier in Otumwee, the most ancient and famous city of the world, female heretics were thrown to the mice.

Dinosaurs seem strange, but that is just because we are mammals biased toward assuming the modern fauna is familiar and normal, and past forms are exotic and alien. Consider that elephants are bizarre creatures with their combination of big brains, massive limbs, oversized ears, teeth turned into tusks, and noses elongated into hose-like trunks. Nor were dinosaurs part of an evolutionary progression that was necessary to set the stage for mammals culminating into humans. What dinosaurs do show is a parallel world, one in which mammals were permanently subsidiary, whereas the dinosaurs show what largely diurnal land animals that evolved straight from similarly day-loving ancestors should actually look like. Modern mammals are much more peculiar, having evolved from nocturnal beasts that came into their own only after the entire elimination of nonavian dinosaurs. While dinosaurs dominated the land, small nocturnal mammals were just as abundant and diverse as they are in our modern world. If not for the accident of the later even, dinosaurs would probably still be the global norm.

We are monsters, even if we disguise ourselves as ordinary people. We are the children of ordinary people but we are not content with that. Inwardly we are consumed with wickedness, outwardly we are grammar school pupils.

There was a world of mutants, men and women who were more than normal men and women, persons who had certain human talents and certain human understandings which the normal men and women of the world had never known, or having known, could not utilize in their entirety, unable to use intelligently all the mighty powers which lay dormant in their brains.

...crazy as two waltzing mice.

Three blind mice walk into a pub. But they are unaware of their surroundings, so to derive humour from it would be exploitative.

Oh,clever... what's the use of that? Are they human beings?

If you think you saw a mouse, you did. And if there is one, there are more.

Animals of the MONKEY class are furnished with hands instead of paws; their ears, eyes, eye-lids, lips, and breasts, are like those of mankind; their internal conformation also bears some distant likeness; and the whole offers a picture that may mortify the pride of such as make their persons the principal objects of their admiration.

I think we're all bugs and mice, and are only different expressions of an all-inclusive cheese.