USO's

We always look up above to see if there is another life watching us, but how about we look down below in our oceans. The deep blue sea, so large and beautiful but at the same time so much mystery behind it. We might not have the technology to go underwater but what if aliens do, what if they have the technology to live and adapt to underwater pressures and the lack of oxygen. Imagine technology that is able to use gravity as a propulsion and what if they are able to travel in the blink of an eye.