This is a Redditor’s theory but one that makes some sense.
When it comes to Fallout 4 there are all kinds of different myths and characters in the game that are specifically there to fuel the mythology of the world. Some of these creatures are buried so deep in the game that there are only certain ways to find them. The Ghoul Whale is one of those creatures and is one that some of the NPCs in the game not only talk about but actually debate.
There has always been some doubt as to whether players would actually get to see the Ghoul Whale, or whether this is something that is just in the game to add to the mythos. According to one Redditor, the creature is actually in the game, in a way that can be unlocked. Part of the issue is that there appears to be a number of signs that Bethesda is going to be focusing more on the underwater world.
The poster has a theory that they can use the bouys in the game in order to find the Ghoul Whale. He’s actually enlisting the help of other Redditors in order to try and make a mod that will better allow him to see what he needs to see. The buoys are supposed to show some kind of way to find the Ghoul Whale. The poster also share a video that better details his game theory and once again hints at the the fact that the DLC that is coming for the game might be focused under the water.