Choiramancy is a method of divination using a pig's bladder.
From the Greek Choiros, a small pig.
Sometimes, when the entrails foretold nothing certain by dissection, the priest made observations from them in a fire: in order hereto he took the bladder, and binding the neck of it with wool (for which reason Sophocles calls the bladders mallodetous kysteis), put it into the fire,
to observe in what place it would break, and which way it would dart the urine.
Archaeologia Graeca V1: Or the Antiquities of Greece by John Potter (1818)
“By Choiramancy: Let us have a great many Hogs, and thou shalt have the Bladder of one of them.” – Rabelais Gargantua and Pantagruel III. xxv. 134.