A cheese with a personality and character all of its own.
One of the foremost makers of cheese, or at least the richest, on the Discworld is Seldom Bucket. He cornered the market in decomposed lactic produce to such an extent that it allowed him to buy the Opera House. (Although Ronnie Soak, with his unique modus operandi, must be a major competitor to the Bucket cheese empire).
Bucket once lost a man, drowned in a vat of curdling milk that was destined to become Lancre Blue. Such is the nature of this cheese that nobody noticed, until he received a customer complaint concerning trouser buttons in the fromage.
Tiffany Aching also makes cheese. But a witch who makes cheese is likely to add that intangible little something extra to the process. Especially if she is trying for a Lancre Blue. And thus was born Horace the Cheese...