Haha nice one. As a kid I had these friends in the neighborhood (Netherlands) whose dad trained Malinois shepherds and sold them worldwide to security services and police units.

In my city are four day marches in the summer where also international military participate. Before dawn, all these soldiers walk from the forest - where they sleep - to the starting point. It was customary for us as kids to wave to the soldiers and wish them good luck and ask for some souvenirs/stickers.

One day my friends had their dog with them and we learned the command 'luid' (loud in English, laut im Deutsch) so the dog would bark. Early in the morning, exhausted soldiers that did not even had their morning coffee, very quiet outside, and then the dog would bark them to shock with our little whispers of 'luid'. Good times.