Horace the Cheese
Even before she knew she was destined for witchcraft, Tiffany Aching learnt how to churn butter and make cheese, magical arts which are at least as remarkable as anything else a witch is capable of.
As with Agnes Nitt and singing, it is so often the case that a young witch will have a particular talent or ability which will be heavily tinged with the Discworld's raw magic - the power always finds an outlet.
So it is with Tiffany's cheesemaking.
Granted, she was trying for a Lancre Blue, a cheese which develops a character and a personality all of its own in the normal run of things. But this is a Lancre Blue brought into being by a witch.
Tiffany soon discovers this is a cheese with a mind and an attitude of its own. When Horace meets the Feegles... well, regard those blue veins so characteristic of the Lancre Blue. Don't they look just like Feegle tribal tattoos to you? And where most cheeses are glad of a muslin wrap, Horace proudly wears a very big kilt about the fullness of his wheel.
Interestingly, in Lords and Ladies (Corgi paperback, p296) there is a passing mention of the Elves raiding the pub in Lancre town and stealing anything edible or potable; Terry remarks that "a couple of rogue cheeses in the cellar put up quite a fight". Relatives of Horace? Cheeses also made by Tiffany - or somebody like her?