Within the bounds of actually funny (if not totally professional) and relatively friendly rivalry between branches or units, what cool dick moves did you run across in service?
In Iraq back in the day I was in a Marine battalion under an Army brigade under a Marine division, so on a base in Ramadi with a lot of Army doggies. They gave us an old Iraqi military building to be our HQ and some barracks, big 2-story concrete block. The prior Army unit had painted their division emblem two stories tall down the side.
So happens it was the Army 1st Division, a green diamond with a red "1" in the middle, and doggies thought it was funny to put us in it. So we got some young jarheads and some paint, dangled them from ropes, covered up the green with blue, added the Southern (Australian) Cross stars and "Guadalcanal" and swiftly turned it into the emblem of the First Marine Division, which was now the largest and most visible emblem on the entire base.
Nothing too mean, but it felt good to paint over the Army's patch and get the Corps looming over doggy territory.