SCP 1128 (SCP)
"SCP-1128 is a massive aquatic creature that hunts down any subject given a full description of the being's appearance through either spoken or written descriptions or visual. While we don't know exactly what it is, we do know that it is large enough to eat whales. Persons infected by 1128 will, without being administered amnestics, grow steadily more terrified of water as time goes on. Should a subject ever be fully immersed in water, they will disappear completely under the surface, regardless of the water's actual depth. Apparently, there was an incident where it dragged a D-class personnel member into a glass of water. In most cases, they will reappear moments later in a panicked state, frantically trying to leave the water. Other cases will have the water will become polluted with blood and debris confirmed to be the remains of the subject. Subjects that have reappeared intact claim that they were transported to a vast ocean where they were pursued by 1128. Interviews with these individuals carries risk of further contamination, as descriptions of the being's appearance trigger further infections."
Ghost Leviathan (Subnautica)
"To me, they are pretty much the embodiment of the fear of the open ocean. Once you reach the Crater Edge the seabed drops away leaving nothing ahead but an empty void. You could fall through it forever if you let yourself. You get a message as you pass the boundary "Warning: Entering ecological dead zone. Adding report to databank." Keep going and an adult Ghost Leviathan will appear to kill you. Then another appears, and another. Aside from some microbes, these are the only things living out in the void. For any you manage to kill, another will take its place. As they grow, they migrate out to the void where they have enough space to keep growing. It's implied that they keep growing their whole lives."