Lycopodium powder is an extremely lightweight substance of a light yellow color. It is harvested from a club moss of the scientific name Lycopodium clavatum, also known as Stag's Horn club moss, that grows in northern United States. It is smooth to the touch, and of course an allergen, so if you are prone to allergic attacks of varied sorts, stay away. The powder is relatively inexpensive, and even a weight as small an an ounce will fill more than a half cup volume measure. When blown or sprinkled into a flame, it erupts instantaneously into a hot, bright, yellow ball of fire. This is a controlled example of what happens in grain elevator explosions where enough surface area is exposed so that the maximum amount of oxygen will be available in the combustion process. The smell of the aftermath is similar to, well, not much that I am aware of. It is like a combination of mushrooms and burnt protein, but that is by no means a definitive truth. Lycopodium powder can be obtained through various online suppliers at a low price. It is not explosive as a powder, only when it is dispersed in the air.