The pistol shrimp... the noisiest creature in the ocean. Colonies of them make a distinct snapping noise that overshadows nearly all other sounds throughout the world's oceans, including the calls of some whales. In fact, they are so loud, their snapping sounds interfere with military and scientific sonar (so much so, that hostile submarines have used large colonies of pistol shrimps to hide!).
So how on earth does the pistol shrimp, which can be anywhere from a couple centimeters to a couple inches in length, make such a loud sound? They possess an oversized claw which they close shut quickly enough to move water over 60 mph, creating a cavitation bubble in its wake. This bubble exists for a tiny fraction of a second (between 10 nanoseconds and 300 picoseconds), but it becomes so hot (over 8,540F) that it emits light. The cavitation bubble finally collapses and creates a bang as loud as 218 decibels. As a comparison, the space shuttle launch was as loud as 170~ decibels.
Now the next question; why? These shrimp use their super claws to stun prey. The shockwave from the collapse of the shrimp's claw is enough to stun small shrimp and fish and kill them.. without even touching them. They also compete and fight with one another to see who is louder. Overall... this shrimp is pretty awesome.