The Waterphone Megabass is that relatively unknown and peculiar instrument responsible for all those eerie and scary sounds one hears in countless TV shows and movies. Some might say it is even the sound of evil.
It is particularly used in building suspense, mystery, tension, uncertainty, fear or something otherworldly. Whether it's in the background or a part of the soundtrack, there's nothing else out there that sounds like it.
It can be played as percussion or as a string instrument with a bow. It is also sometimes called an ocean harp or AquaSonic Waterphone. The sucker actually has water in it too, hence the name. :-)
Here are a couple short examples of it in use.
For something relatively small, it sure packs some punch.
Each one is made bespoke / to order, which adds to its allure. More can be found about its orgins and history on the Waterphone company website.
Just one of those things out there that always made Bob wonder where the hell those sounds came from.