The mantis shrimp lives on a different planet that happens to share Earth.
Start with the eyes. Two stalks, each independently mobile, each carrying about ten thousand light receivers. Where most animals split the visible spectrum into red, green, and blue and let the brain do the math for everything else, the mantis shrimp doesn't bother with math. Each color of the rainbow has its own dedicated receptor. Plus four channels in ultraviolet. Plus circular polarization — a property of light most physicists need a $40,000 instrument to measure. The mantis shrimp gets it through the eyeball.
There's no good way to translate what a mantis shrimp sees. Imagine you've spent your whole life listening to music in mono, and one morning you wake up to seven-channel surround sound playing the same song. That's roughly the upgrade — except for color.
Now the punch.
Sheriff Six-Legs has done a lot of his career around fast critters. Trap-jaw ants. Tiger beetles. Hummingbird hawk-moths. None of them touch this. Two raptorial appendages on the front of the mantis shrimp's body are spring-loaded clubs. The latch releases, the clubs swing, and they go from rest to forty-five miles an hour in two thousandths of a second. Acceleration: about ten thousand g.
That's not the impressive part.
The impressive part is what happens to the water. The clubs move so fast they leave a vacuum behind them — a tube of pure nothing in the shape of a punch. Water rushes in to fill the vacuum. When it slams together, the collapse generates a shockwave, a flash of light briefly hotter than the surface of the sun, and a secondary blow nearly as hard as the first. The mantis shrimp punches twice with each strike. The second punch is light.
A snail's shell, on the receiving end, doesn't crack so much as detonate.
A captive mantis shrimp once cracked the glass of his own aquarium with a punch aimed at a passing reflection. Marine aquariums keep them in solo cells now. Plate glass doesn't stop them. Acrylic is required.
The Sheriff doesn't recommend trying to win a draw with a mantis shrimp. Not as a fish. Not as a snail. Not as a piece of aquarium glass.
If you're trying to be a mantis shrimp, the news is also not good — the species mate for life and the females are picky. The males who don't impress die alone in their burrows under the coral. The males who do, also eventually die alone in their burrows under the coral, just slightly later, and with company on the way out.
Pound for pound, ounce for ounce, watt for watt, the mantis shrimp is the most over-engineered organism that ever crawled out of a tide pool. The sheriff doesn't make a wanted poster for her. He makes a salute.
If they come back, so does she.
The difference is, when she comes back, she comes back at fifty miles an hour. Carrying a sun.