Thermite
Thermite is not safe to make at home. It releases ultraviolet light which can damage the eyes. It also makes a very hot flame that can melt iron. It is extremely difficult to extinguish. Streams of molten iron can flow out of a thermite mixture, igniting everything it touches. Some metals can boil and burst into flames when placed in thermite, such as zinc. If it is preheated then ignited, thermite can burn very fast, releasing a huge amount of heat and light. If it is dropped in water it can boil water very fast, making an explosion. Dropping it on ice can make the ice explode, however it is safe to drop it into a three-liter beaker filled with lightly moist sand.