Bloop

The Bloop, commonly known as the Giant Sea Monster/Creature, is a legendary giant-underwater creature. The creature's sounds we're caught by the USA back in 1997. Though in 2012, people speculated that the sounds we're created by a marine-animal.

Sound Detection
The sound got detected by the Equatorial Pacific Ocean autonomous array, which is a hydrophone system which is used under the sea. The system was created by the NOOA Laboratory, which is controlled by the USA.Originally the system was designed to detected Soviet submarines. The system suggested that the Bloop sound is very similar to a ice-quake sound effect. This information got confirmed in 2008.

Animal Origin
One of the scientists didn't believe that the sounds we're made by human-bombs or any geological event. He stated that the audio mainly sounds resemble a alive-creature, to which he added that the sound did sound like an animal, and that it it's much more powerful then any other animal. It is believed that the creature lives in the Antarctica.

Secure Contain Protect SCP Foundation
In the SCP Foundation, there is a huge-gaint creature named SCP-169, also known as The Leviathan. The creature mostly resembles the Bloop creature.