There is a six-minute segment in a Charlie Chaplin film that pokes fun of the trickery of WWI American camouflage artists in France. The film, a silent comedy called Shoulder Arms, was released in October 1918, just as the war was ending. There is more information here, and there's also a helpful description of it in Kenneth Schuyler Lynn, Charlie Chaplin and His Times (NY: Simon and Schuster, 1997), pp. 222-223—
For reconnoitering purposes, Chaplin encases himself in papier-mache bark and becomes a tree. His camouflage enables him to position himself near three German soldiers who happen by and start to build a campfire. Inevitably, they find that they need more wood. One of them grabs an ax and volunteers to get some. After taking a healthy lick or two at another tree, he decides that he prefers the looks of the Charlie-tree. Terrified but resolute, Charlie knocks the ax-wielder out with a sneak blow from one of his branchlike arms and similarly disposes of his two companions. While still camouflaged, he then saves the life of an American sergeant who has been apprehended for spying…
