I believe that is the Mantis shrimp, not the bullet shrimp (though I suppose “bullet shrimp” may describe these types of shrimp in general). This also may be a mix-up with the Pistol Shrimp, which is a shrimp that believes in the 2nd amendment.
This is the Pistol Shrimp:
They don’t look as cool as the Mantis Shrimp, but they have the name “Pistol Shrimp” for a reason. They are like the Mantis Shrimp in that they enjoy murdering innocent creatures in bizarre ways. But the Pistol Shrimp actually fires bubbles to kill their prey:
But the greatest real-life gunslingers have to be the pistol shrimp, aka the snapping shrimp, hundreds of species with an enormous claw they use to fire bullets of bubbles at foes, knocking them out cold or even killing them. The resulting sound is an incredible 210 decibels, far louder than an actual gunshot, which averages around 150.
So yeah, you can actually hear these puppies snapping when you’re in the water. The sound comes from the explosion of the bubble they create, not the claw itself snapping.
Also, in regards to the Mantis Shrimp, they’ve done studies now trying to see the extent to which color variations the Mantis Shrimp sees, and apparently they’re not that good at distinguishing differences between colors. They’re trying to figure out why their eyes got so many damn cones if they can’t tell the difference between powder blue and teal.