The Amazing Peacock Mantis Shrimp

The peacock mantis shrimp is by far one of the coolest animals ever, rivaled only by cats, jackalopes, dinosaurs, unicorns, and dragons.  First of all, they are extremely colorful.

PRETTY LITTLE SHRIMPS WITH KILLING POWERS!

They're this colorful because potential mates can detect wavelengths on the body of the shrimp.  They also use their rainbow awesomeness to scare away predators.  Peacock mantis shrimp aren't actually shrimp; they belong to the order Stomatopoda.  They commonly grow to between 6-12 inches, though in some rare cases they grow longer.  Peacock mantis shrimp have raptorial appendages, a single pair of maxillopods, three sets of legs for walking, and five pairs of legs (don't know what those are for).  They hold themselves like praying mantises, hence their name.

 Peacock mantis shrimp have the most advanced color vision in the world.  Their eyes have 16 color receptive cones, four of which detect ultraviolet light and four others detect polarized light.  To put this into perspective, all the colors we see are composed from 3 color receptive cones.   "Where we see a rainbow, the mantis shrimp sees a thermonuclear bomb of light and beauty (The Oatmeal)."

You'd think that they wouldn't be able do much damage to anything, but YOU ARE WRONG, BIG TIME WRONG.  They are also one of the most violent creatures on earth.  Remember those raptorial appendages?  Those accelerate at the same velocity as a gunshot from a twenty-two caliber rifle and in less than three-thousandths of a second can strike prey with 1,500 Newtons of force.  To put this into perspective some more, if a human could move one of their arms 1/10th of that speed, they could throw a baseball into orbit.  Their limbs move so fast the water around them BOILS in a process known as supercavitation.  When the bubbles collapse, they produce an underwater shock wave, so even if the peacock mantis shrimp misses the prey dies.  The force of the collapsing bubbles also produces temperatures in the range of several thousand Kelvins and emits tiny bursts of light called sonoluminescence.  They also like dismembering their prey.  By the way, they like to eat crabs, octopi, mollusks, and oysters.  Their limbs are so resilient (They have to be, if you kill your prey with shock waves), researchers are studying the cell structure of the shrimp to make body armor for combat troops.  Aquariums don't usually have mantis shrimp because they kill anything they share a tank with and can break the glass of the tanks.
Here's a video showing the shrimp in action:




I dare you to find something cooler.

https://bioweb.uwlax.edu/bio203/s2014/hruska_mark/nutrition.htm
http://theoatmeal.com/comics/mantis_shrimp
http://en.wikipedia.org/wiki/Mantis_shrimp