Peter Lorre had a reputation as an actor who liked to play tricks on his fellow actors during the course of making a film. The picture below is a rarity in that it is the only known piece of photographic evidence in existence that shows one of his co-stars turning the tables on this inveterate prankster.
The film "The Boogie Man Will Get You" was made at the height of WWII. The producers, in an attempt to use the powerful influence of the movie medium to educate those on the home front as to the proper way to remain strong and healthy during wartime, decided to include a message about the importance of continuing to receive regular check-ups while waiting for loved ones to return from military service.
As it was planned, the scene was to show the character of Dr. Lorencz counseling a female patient on the importance of eating a well balanced diet that includes all four major food groups. Actress Mona Loudlie had other plans.
After clueing in the still photographer on the set as to what was about to transpire, she waited for the perfect moment. Peter, as scripted, concluded his lecture with, "... So you see, Mrs. Parker, it is very important that you, like all the wives and sweethearts of our soldiers overseas fighting the Axis, keep healthy by eating three square meals a day." At this point she was supposed to have said according to the script," Yes, Dr. Lorencz. I understand completely what you are saying. We owe it to our brave servicemen to maintain our fitness and stamina while they are away." Instead, what she improvised, with previous approval of the director, unbeknownst to Lorre was, "Fine, Dr. Lorencz. Now, how about my annual breast exam?" She then lifted up the front of her blouse. The still photographer, in league with the pranksters and waiting in readiness, snapped this shot at that precise moment:

The surprise on Peter's face in this shot speaks for itself. Needless to say, there was much jocularity and frivolity on the set as soon as he realized he'd been had!
Unfortunately, the studio executives were shocked and dismayed by reports of this incident. As a result, the whole war time public health message idea was scrapped along with this unscripted scene development.
This original photo, of which I own the only one ever made, is all that remains to document what took place that day.