Warships Full of British Sailors Pretending to Be Women on Merchant Ships
During WW2 German U-boats were sinking most of the Allied merchant fleet. The British noticed that the submarines doesn't go near any ships that could actually shoot back, so it made sense to disguise the warships as small merchant ships.
They also noticed that the subs surfaced when they attacked. So they came up with this idea: lure the Germans to the disguised ships, then blow them to smithereens when they broke the surface. This was not by itself a particularly crazy idea.
But this disguise had to be convincing, so this is where things got downright weird. The sailors donned costumes, so they wouldn't look like military when viewed through a periscope. Some of them dressed as women and walked around on deck snuggling with other dudes. Some dressed with fake parrots, or in blackface.
They even choreographed elaborate acts where once a U-boat was spotted, they'd act like panicked civilians and begin to abandon ship, making a show of running into each other and tripping and falling. Some would even jump into the lifeboats and pretend to leave someone behind, and he would stand on the railing screaming for them to come back and get him.
Meanwhile, guns were hidden all over the ships, behind normal-looking hatches, inside shipping crates, under fake smokestacks, behind false walls and inside fake lifeboats. Once the unsuspecting U-boat surfaced for the easy kill, the captain pulled a lever, all the trapdoors would open and guns would point out the sides and blow the baffled Germans to hell.
Apparently at least 70 German submarines actually fell for this, and 14 of them were sunk. This makes cross-dressing sailors the seventh leading cause of death for World War I German submariners.