I had a dream I was swimming in a lake with a group of people. We all knew each other, but I can't remember their faces and couldn't put names to them. At one end of the lake was a wooden dock, but it was built into a cliffside, the buildings and structure of the dock was more vertical than typical. At the other end of the lake was a glass wall. On the other side of the glass were the fish and wildlife of the lake. I could see all sorts of colorful fish beyond the glass, and some sharks as well, though they were calm creatures swimming aroubd happily and peacefully. We swam back and forth around this lake a lot, getting out onto the dock every now and then to take part in activities and games of sorts. Then we were all treading water at the glass wall looking at the fish. As I watched, I saw a small vibrant blue and yellow fish swim from somewhere I could not see directly up to me. It had found a way past the glass, or the glass was not sealed at some point, or had come loose in some way. But the fish was incredibly pretty and seemed very happy to be swimming up to me. I laughed and we swam together in small circles for a moment. Then more colorful fish began appearing around us, all of them discovering the way through. There was a moment of excitement, and the everyone began to panic as they all realized that any of the fish could swim through. I felt the same fear, but was not able to identify the piece of information that this fear was sourced from. I just knew that if any fish could make it past the glass there was something terrible to be feared. We all began to swim across the lake to the dock. I looked back periodically towards the glass as we swam, and saw a great big shadow of something in the water. The shape was at least 50 feet in length, and I could slowly make out details of its form as we kept swimming away. It had a face like an alligator, long and narrow, and teeth in rows like a shark. It's body was narrow as well, with sleek fins on either side and dorsal as well. It moved through the water swiftly and effortlessly as though it was propelled by its will alone. I watched it eat several larger fish, as it tore through the water. It was making its way towards us, but didnt seem to be in a hurry. We made it to the dock and all began to climb up. I was second to last to make my way up. once we were all safely on the first level of the vertical dock, I watched from eyes that weren't my own as the creature (people were calling it a shark, but it was not) ate what looked like a large goat that had somehow fallen in the lake. I then watched from those eyes that weren't mine as the creature swam with the movement of the water to an outlet of the lake that flowed into a tall waterfall and it went over into the waters below. From their I lost track of the creature as it made its way into open waters beyond. Everyone seemed to ease at the creature being gone, but I felt a deep knawing uneasiness knowing that it had made its way into the open world. Someone said "The shark is gone, it should be safe to swim again" but I felt like I knew there was an omission in that, that we were safe but in our safety a danger had been unleashed on others. Then I woke up.