That is “guerrilla warfare.”
I am not even going to ask for how long you thought it was “gorilla warfare.”
Or was that just me?
Seriously though, I had no idea: Guerrilla warfare comes from Napoleon.
Or more specifically, the Spanish that fought against Napoleon.
Strategically, guerrilla tactics make sense.
For who would be foolish enough to stand up to a clearly superior force?
You simply blend into the crowd, organize in secret, and fight on your own terms at a later date.
Guerrilla warfare, done well, can make military occupation nearly impossible.
It might even work in office politics, if you think about it.
The word “guerrilla”—“ small war” in Spanish—was coined in reference to the Peninsular War of 1808–14, which began when Napoleon invaded Spain. Melting into their country’s mountains and inhospitable terrain, the Spaniards tortured the French, making it impossible for them to profit from their superior numbers and weaponry. Napoleon was bedeviled by an enemy that attacked without forming a front or rear. The Cossack fighters who undid him in Russia in 1812 had learned a lot from the Spanish and perfected the use of guerrilla warfare; their harassment caused far more damage than anything the rather incompetent Russian army could inflict.
-Robert Greene, The 33 Strategies Of War