An electric display waterfall that Captain Stottlemeyer had in his office. Before his wife came in, he was advised that he needed to run his electric waterfall that she gave him, in order to show her that he appreciated her presents.
Receiving notice too short to go out to fill water from a fountain or cooler, Stottlemeyer just put his morning coffee onto the electric display, and given that coffee was flowing down it, he dubbed it a coffeefall.