‘It’ was a Psammead, which looked a little like a monkey but had eyes which came out on stalks like a snail’s, and it was furry all over. Five children found it when they were digging in a sandpit. It was thousands of years old. It gave them a wish a day, but whatever they wished for was guaranteed to fade at sunset, when everything went back to normal. The difficulty was to think of really good wishes: another was to avoid saying thoughtlessly at the critical moment, ‘Oh, I wish...!’ and getting something they did not really want at all. Every wish brought them into difficulties, but most gave them at least a moment of surprise and satisfaction, if not always of great delight. The Psammead was not the easiest of pets, and was extraordinarily nippy (in two senses) when annoyed.