So I went through the whole Dunwich Borers and swam all the way to the bottom of the tunnel just to find a couple mini nukes and kremvhs tooth nowhere to be found. Is there any other way to get it? I read somewhere that if you get it off a legendary enemy then it won't be down there any more however I though you couldn't get that weapon off a legendary enemy and I don't have it stored anywhere so I know I didn't pick it up. Any advice or anybody have the same problem?

You might want to ask for this to be moved to the Hints and Spoilers forum as this is a No Spoilers section.

You are correct that the wiki states that if you have picked one up from a Legendary, it won't spawn on the altar. Unless you are on the PC and can use the console to give it to yourself, you will have to check your followers, settlers and storage again.

Known bug

If you're on PC, its baseid is 0022576d.

Oops sorry didn't mean to post any spoilers guys but I'm on ps4 thanks for the help though looks like it's just a bug Smh

It was a cruel joke played on you by nyarlathotep.

More than likely you already know this: The altar is NOT at the bottom of the shaft. It's at the end of a side passage with an opening in the shaft about 10 feet up from the bottom of the shaft.

Just be aware that this weapon can be scrapped with no warning, even though it has a "star."

Be sure to turn on your pip boy light and look around, it may have been knocked onto the floor or something.

Yea trust me I searched everywhere for it down there and I never scrap or sell any weapons never mind legendaries so unless it got thrown into my workshop and scrapped when I was building my settlement that would be the only way but it looks like I'm going without this weapon not that I play a melee build anyways but I just like collecting the unique weapons