I almost busted my gut laughing last year when I first gave my half grown Mallards a big enough pool they could dive underwater in. The entire time they were growing up they did everything as a group, never more than inches apart. So they get into this pool, swimming around having a grand time when one of them would "dive" under, kicking and throwing water, this startled the others and they jumped out of the pool and ran across the pen at full speed. By time the one duck surfaced he was alone and would freak out, see the others and run to them as fast as possible. They'd all look at the pool like "what happened?" After a bit they'd get back in and in short order the same process would play itself out, hilarious.