An aquatic great unknown line

At last, I found (said) a great unknown line that is not from Facebook. It was pouring today, pouring crazy as if it was a nasty cold day. I don't mind, it will be good for the grass. But as it kept pouring and pouring, and the end of working day was getting closer, we all looked wearily at the window. It kept pouring. One of my colleagues said, philosophically: "Well, there's nothing here that can kill us." To which I reply: "As long as you have gills." If I may say so myself, it was funny.