Pistol shrimp look like they punch their enemies when threatened. What they are really doing is far crazier. The shrimp snaps its claw together and a snapping sound is actually heard. It isn’t the sound of the claw, though. Slow motion cameras reveal that the snap creates a bubble.
The bubble travels at upwards of 60 miles per hour and vaporizes the water around it in an instant. For an instant, the bubble is as hot as the sun and creates a type of shock wave that collapses the bubble. It is so powerful and fast that it stuns and even kills its adversary. So, the punch actually comes from a super hot bubble, not the claw. The pistol shrimp is less than an inch long.
The crack that it makes is actually a deafening sound, one as loud as a gunshot. The sound itself stuns small fish and crabs, which then gives the shrimp time for its supersonic heat bubble attack. The pistol shrimp is also known as the snapping shrimp.