A round egg-shaped metal device, roughly the size of an basketball. It's core is a delayed phosphorus fuse linked to an electric current. The thing is weighed so that, when thrown, the thicker side of the egg is on the bottom. Ten seconds after the fuse is pulled, the phosphorus will ignite with the hard-packed aluminum shavings and rust, creating a bubbling mass of molten liquid which is the hottest non-nuclear chemical reaction this side of a nuclear explosion. The C4 packed into the top of the egg then detonates, sending the hot stuff straight down into whatever happened to be underneath.