The Vanishing Private is a Donald Duck short released 25 September 1942.
Summary[]
Donald Duck is camouflage painting a cannon, but with yellow, green, and red stripes and black dots. Sergeant Pete sees it and scolds Donald, explaining that it needs to painted so it can't be seen. He demands that Donald re-paint the cannon to make it "hard to see." Donald walks to the "Experimental Laboratory: Camouflage Corps", disregarding the "Keep Out" sign. He finds some "invisible paint," which he tests with his finger, then uses to paint the cannon.
When Pete returns, he is shocked to find the cannon seemingly gone, believing it to be stolen. He bonks his head on the underside of the cannon and discovers Donald inside. He blows hard into one end of the barrel, sending Donald out the other end and into the bucket of invisible paint. When Donald runs away, Pete finds out Donald has become invisible by seeing his footprints on the ground. Donald then swims across a lake, but the invisible paint doesn't wash off.
Pete continues to chase Donald through a field of flowers, until he accidentally throws some of the flowers on Donald, revealing his outline. Pete tries to catch him, but he gets away again. However, this gives Pete an idea. The General arrives and sees Pete jumping around a tree while singing "Here We Go Round the Mulberry Bush" and throwing flowers. Pete asks the General "Did you see a little guy that you can't see?" The invisible Donald then puts a cactus down Pete's pants, making him scream and jump around like a madman.
Donald then walks around a nearby kitchen and sees some pies in the window, so he takes one of the pies and eats it. Pete notices this, but Donald throws the pie in Pete's face. Donald is then skipping a rope, which angers Pete, so he chases him. Donald trips Pete, sending him literally under the grass, under some soldiers, and out again into the arsenal building, where he gets hold of several grenades and begins blowing things up to stop Donald, starting with a tree that flies into the air and floats down. The General is scared when Pete runs towards him, and hides behind a nearby power pole. The General tries to reassure Pete and stop his rampage, but Donald stands behind the General, and pokes Pete in the rear with the General's sword, the startled sergeant jumps into the air and onto the General, releasing all of the grenades, which injure them in the explosion.
Later, Pete is locked up in a padded cell, wearing a straitjacket and chains, as he has been declared insane by the Army for his actions. He pleads to Donald, who is on guard duty and no longer invisible, to go tell the General of his sanity, but Donald refuses, asking Pete "Do you think I'M crazy?" and whistles "The Army's Not the Army Anymore."