The Navy first used acoustics to measure the ocean depths in the 1930s. And at the time, the area they thought to be the bottom of the sea would change throughout the day. But it turns out the sea bottom was actually a layer of animals that travel en masse. And they moved thousands of feet below the water’s surface throughout the day and night. So they call it the ocean “twilight zone,” and it’s chock full of insane marine life.
This four-inch annelid was only recently discovered in the Coral Triangle, between Indonesia and the Philippines. It gets its name on account of the 10 tentacle-like appendages on its head, which it uses to collect floating food particles.