Wildfire is an extremely dangerous substance made by alchemists in the series. It is said to be green, and will burn anything until it snuffs itself out. It was a favorite method of execution by the Mad King Aerys, and is most well-known for the Battle of the Blackwater, where, on Tyrion Lannister's command, it was flung by the jar onto ships in Stannis Baratheon's fleet.
A Clash of Kings Edit
Tyrion Lannister Uses the Wildfire to burn Stannis Baratheon ships During the Battle of the Blackwater in order to defend King's Landing. The Wildfire burns king Joffrey's own ships along with Stannis army.