The Bloop is a mysterious sound detected underwater by the U.S. National Oceanic and Atmospheric Administration (NOAA) several times during 1997.
There is no idea what caused the sound, but there is speculation that it was biological based from its audio profile. If it was, then that would be the loudest biological sound known to man. It's several times louder than any other biological sound on the planet. That's very frightening when one realizes that The Bloop's source was detected to be only 500 miles from R'lyeh in the South Pacific, which is where Cthulhu is supposedly napping. Maybe it was his alarm clock?
If so Mr. Cthulhu, I want you to know : "Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn!"
Who is Cthulhu you ask? Well, he's the Great Old One waiting to awaken and devour the earth. But, if you're a part of his cult he'll eat you first, so it'll be okay. Cheers!
There are a ton of ocean cryptids. Remember Jaws? Yeah, the big shark from the movie that ate everyone and was near unkillable. Jaws was based from a creature known as the Megalodon, an ancient giant shark. There's also sightings of giant squids, sea serpents, giant aquatic centipedes and a ton of other things that'll make you crap your pants that possibly still exist out there.
This isn't being pulled out of someone's ass either. Ever heard of a narwhal? People used to think they didn't exist either. What about giant squids, colossal squids, and megamouth sharks? They're all real creatures that'll give you nightmares.
Enjoy your next trip to the beach!