Thaumivore

"I knew it wasn't killed,'' growled Vimes.' “There were no bits. It was too neat. It was sent somewhere by some sort of magic, I bet. Look at it. It's bloody impossible! It needs magic to keep it alive!”

“What do you mean?” said Lady Ramkin, not tearing her gaze from its armoured flanks.

What did he mean? What did he mean? He thought fast.

“It's just not physically possible, that's what I mean,” he said. “Nothing that heavy should be able to fly, or breathe fire like that. I told you.”

“But it looks real enough. I mean, you'd expect a magical creature to be, well, gauzy.”

“Oh, it's real. It's real all right,” said Ramkin bitterly. “But supposing it needs magic like we need, like we need . . . sunlight? Or food.”

“It's a thaumivore, you mean?”

“I just think it eats magic, that's all,” said Vimes, who had not had a classical education. “I mean, all these little swamp dragons, always on the point of extinction, suppose one day back in prehistoric times some of them found out how to use magic?”

"There used to be a lot of natural magic around once,'' said Lady Ramkin thoughtfully.

“There you are, then. After all, creatures use the air and the sea. I mean, if there's a natural resource around, something's going to use it, aren't they? Then it wouldn't matter about bad digestion and weight and wing size and so on, because the magic would take care of it. Wow!”

But you'd need a lot, he thought. He wasn't certain how much magic you'd need to change the world enough to let tons of armoured carcass flit around the sky like a swallow, but he'd bet it was lots.

All those thefts. Someone'd been feeding the dragon.

He looked at the bulk of the Unseen University Library of magic books, the greatest accumulation of distilled magical power on the Discworld.

And now the dragon had learned how to feed itself.

***

Guards Guards - p199-200