Back in the Civil War, the Confederate Secret Service designed a powerful weapon: A bomb designed to look like a piece of coal.
Bibliography
Daily Appeal (Memphis, TN). “Letter from Richmond”, May 11, 1864.
“Greyhound.” Naval History and Heritage Command. https://www.history.navy.mil/research/histories/ship-histories/confederate_ships/greyhound.html
The Cleveland Leader (Cleveland, OH). “The Coal Torpedo”, May 19, 1865.
The Evening Star (Washington, DC). “Terrible Disaster on James River”, Nov 28, 1864.
Welker, David. “Explosive Coal: Bombs Hiding in Plain Sight “ Studies in Intelligence Vol. 66, No. 1 Last modified Mar 2022. https://www.cia.gov/resources/csi/static/Articler-Covert-Coal.pdf
Media Sources
“Coal Torpedo.” (1907) https://en.wikipedia.org/wiki/File:CoalTorpedo.jpg
“Greyhound steamer.” (before Nov 1864). https://en.wikipedia.org/wiki/File:Greyhound_steamer.jpg
“Courtenay CSA.” (1860s) https://en.wikipedia.org/wiki/File:Courtenay_CSA.jpg