He's done some whimsical, vaguely similar things before. For the ice bucket challenge he built a whole rig to do the dumping. And my favorite, released a bunc

He's done some whimsical, vaguely similar things before. For the ice bucket challenge he built a whole rig to do the dumping. And my favorite, released a bunch of mosquitos into the crowd during his Ted talk on malaria. So not really out of character, at least for post-Microsoft Gates.