Susan did not know much about history. It always seemed a particularly dull subject. The same stupid things were done over and over again by tedious people. What was the point? One king was pretty much like another.

The class was learning about some revolt in which some peasants had wanted to stop being peasants and, since the nobles had won, had stopped being peasants really quickly. Had they bothered to learn to read and acquire some history books they'd have learned about the uncertain merits of things like scythes and pitchforks when used in a battle against crossbows and broadswords.

She listened half‑heartedly for a while, until boredom set in, and then took out a book and let herself fade from the notice of the world.

SQUEAK!

Susan glanced sideways.

There was a tiny figure on the floor by her desk. It looked very much like a rat skeleton in a black robe, holding a very small scythe.
Susan looked back at her book. Such things did not exist. She was quite certain about that.

SQUEAK!

Susan looked down again. The apparition was still there. There had been cheese on toast for supper the previous night. In books, at least, you were supposed to expect things after a late-night meal like that.
'You don't exist,' she said. 'You're just a piece of cheese.'
SQUEAK?

When the creature was sure it had got her full attention, it pulled out a tiny hourglass on a silver chain and pointed at it urgently.

Against all rational considerations, Susan reached down and opened her hand. The thing climbed on to it - its feet felt like pins - and looked at her expectantly.

Susan lifted it up to eye level. All right, perhaps it was a figment of her imagination. She ought to take it seriously.
'You're not going to say something like "Oh, my paws and whiskers", are you?' she said quietly. 'If you do, I shall go and drop you in the privy.'
The rat shook its skull.
'And you're real?'
SQUEAK. SQUEAKSQUEAKSQUEAK­-
'Look, I don't understand,' said Susan patiently. 'I don't speak rodent. We only do Klatchian in Modern Languages and I only know how to say "My aunt's camel has fallen in the mirage". And if you are imaginary, you might try to be a bit more . . . lovable.'

A skeleton, even a small one, is not a naturally lovable object, even if it has got an open countenance and a grin. But the feeling . . . no, she realized . . . the memory was creeping over her from somewhere that this one was not only real but on her side. It was an unfamiliar concept. Her side had normally consisted of her.

The late rat regarded Susan for a moment and then, in one movement, gripped the tiny scythe between its teeth and sprang off Susan's hand, landed on the classroom floor, and scuttled away between the desks.
'It's not even as if you've got paws and whiskers,' said Susan. 'Not proper ones, anyway.'

The skeletal rat stepped through the wall.

Susan turned back to her book and ferociously read Noxeuse's Divisibility Paradox, which demonstrated the impossibility of falling off a log.

© Terry Pratchett