Historical accounts of incendiary pigs or flaming pigs were recorded by the Greek military writer Polyaenus[1] and by Aelian.[2] Both writers reported that Antigonus II Gonatas' siege of Megara in 266 BC was broken when the Megarians doused some pigs with combustible pitch, crude oil or resin, set them alight, and drove them towards the enemy's massed war elephants
(Wiki)