This column is part of a series where Verge staffers post highly subjective reviews of animals. Up until now, we've written about animals without telling you whether they suck or rule. We are now rectifying this oversight.

At the end of the island I noticed a small green frog. He was exactly half in and half out of the water, looking like a schematic diagram of an amphibian, and he didn’t jump.

At last I knelt on the island’s winter killed grass, lost, dumbstruck, staring at the frog in the creek just four feet away… And just as I looked at him, he slowly crumpled and began to sag. The spirit vanished from his eyes as if snuffed. His skin emptied and drooped; his very skull seemed to collapse and settle like a kicked tent. He was shrinking before my eyes like a deflating football. Soon, part of his skin, formless as a pricked balloon, lay in floating folds like bright scum on top of the water: it was a monstrous and terrifying thing. I gaped bewildered, appalled. An oval shadow hung in the water behind the drained frog; then the shadow glided away. The frog skin bag started to sink.

Annie Dillard, Pilgrim at Tinker Creek

The infinite complexity of nature lends our world beauty, but the cost of that beauty is pure horror. "Nature is, above all, profligate," says Annie Dillard, author of that hollow-frog fable you just read. "Nature will try anything once."

One of the things nature has tried is the giant water bug, which belongs to a family of insects formally known as Belostomatidae. Their existence is necessary in one sense — there are plenty of frogs to eat! — but inexplicable in a human sense, the kind that demands to know the purpose of a thing. And there appears to be no purpose for the giant water bug, except to inflict terror and suffering. It is nothing more than that oval shadow in the water; a grim automaton that reaps the lives of other creatures that are more compatible with the ergonomics of human sympathy.

Alien life isn't just the stuff of fiction

Astute humans know that alien life isn’t just the stuff of fiction. It is here, on Earth, and it is just outside your door. It can be found in the nearby meadow, in the backwoods, in the rivers and lakes, and in the impossibly dark depths of the ocean. The giant water bug is one of those aliens.

Most species in Belostomatidae are large, exceeding 12 centimeters, and their contours are emphatically hostile to world around them. They have two abdominal appendages that allow them to suspend their bodies below the water’s surface, a hardy beak for invading the bodies of prey, and large raptorial legs covered in spines. The only reasonable conclusion one can make upon examining this hateful anatomy is that the giant water bug is a machine built for killing.

It’s not just that the members of the Belostomatidae clan are inveterate killers. Other psychopathic predators, like the domestic cat, have earned a seat in the Justice League of species because they offer us something more than extravagant bloodshed. It’s how the water bug kills, and how little else it provides amid the slaughter, that makes it so abhorrent.

The giant water bug will stalk almost any small creature it can handle, including insects, tadpoles, small fish, salamanders, and even frogs. And then it waits. It is an ambush predator — meaning it uses deception to catch its prey unawares. When the time is right, the object mistaken for a giant leaf springs into action, grappling its hapless victim with its clawed forelegs. Then the true horror begins. The bug extends its rostrum into its hostage, injecting a vicious digestive saliva that literally liquefies its internal organs, then sucks them out — leaving behind, sometimes, nothing more than the hollow skin of a vanquished frog. Or maybe a snake:

But what’s really confounding is the suffering. The "bite" of the giant water bug is one of the most painful that any insect can deliver, but it has "no medical significance." In other words, the water bug inflicts pain for the sake of pain. That’s the kind of fundamental evil — meaningless, indifferent, and inescapable — capable of challenging the wisdom of ostensibly benevolent gods. A frog captured by a giant water bug in a pond disturbs the water’s surface, each ripple a telegram of terror. This will happen over, and over, and over, and over again, billions of times, until life and death and pain become part of an indistinguishable continuum, such that the ripples emanate endlessly as a kind of cosmic background radiation of suffering. It is all around us, even when we don’t see it or feel it.

So that’s the cost of beauty. The vast extravagance of nature provides everything, and then takes everything. It is entropy in the abstract, but it is the form we’re most intimately familiar with.

Suffering is the cost of beauty

Of course, the giant water bug has no more purpose behind its existence than the frog it eats, and incessantly demanding a reason for its presence is useless except when it helps us understand our own condition. Like the giant water bug, human beings — rapacious and selfish — have dominated every other species on the planet. Even our tools are similar to the water bug’s. Where the bug uses its beak to penetrate its prey, humans use captive bolt pistols to stun animals before they are slaughtered. That’s not to say we are all the same, but we are similar: our lives made compatible by the shared experience of being thrown into an insane world filled with murderous danger and then being asked to survive.

For highlighting the absurdity of my own existence, I give the water bug a token 1 out of 10 — which is about all my curious self-satisfaction is worth in a world where cute little frogs are literally being liquefied by giant bugs.