https://www.facebook.com/photo.php?fbid=1335452917949428&set=pb.100044541964865.-2207520000&type=3 GZ
Of course there are all sorts of aquatic creature and monster stories.
https://www.britannica.com/topic/Cthulhu , https://lovecraft.fandom.com/wiki/Cthulhu
https://en.wikipedia.org/wiki/The_Monster_That_Challenged_the_World#Plot
https://en.wikipedia.org/wiki/Creature_from_the_Black_Lagoon#Plot
https://en.wikipedia.org/wiki/The_Shape_of_Water#Plot
https://en.wikipedia.org/wiki/The_Abyss#Plot