Explosive Coal and Camouflage

Circa 1942-1945

This lump of coal was developed by the United States OSS during WWII. Within it, is a hollowed out centre, filled with an explosive. The camouflage kit they included with it, was to paint the lump of coal into the exact colours of the local coal you were inserting it into. Then, when the enemy combatants threw the coal in the fire, the spy coal would detonate.