Undermined by Flaming Pigs

"At this juncture the military advantage lay decidedly with the king; he possessed by far the largest number of fortified castles and he had at his command a professional mercenary army. A party of rebels took refuge in the castle at Rochester; John besieged it, and helped to undermine it by strapping burning torches to a number of pigs. The animals were herded into wooden galleries built beneath the stronghold and set it ablaze. This was one of the less formal techniques of medieval warfare."

-- from Foundation: The History of England from Its Earliest Beginnings to the Tudors, by Peter Ackroyd