If someone said “humans suck, but nature is a perfectly beautiful creation 😍” what examples would you think of that show nature being (1) independent of humans and (2) brutal and grotesque?

Humans are part of nature.

I agree. The boundary can easily become diffuse or even silly.
However, there’s a reason I asked what I asked. My ultimate purpose is to show that existence is not perfectly designed, that sometimes it is brutal and grotesque. Unfortunately, people often retort saying nature is brutal and grotesque because of humans. So, by focusing on non-human nature, I’m sidestepping the retort.
- This feels like homework.
I always though the distinction between natural/unnatural is completely meaningless. We do not consider animal intelligence and its products "unnatural" but we somehow do this for humans.
- I don't know, plastic feels fairly unnatural

Some examples in no particular order:

Cowbirds lay eggs in other birds' nests, and if the other bird kicks their eggs out, the cowbird will come back and destroy the nest.
You've probably heard of female black widows eating the male after mating, but did you know that this is so common among spiders that the males of some species are literally hardwired to automatically die during or after mating? Makes the whole process easier and prevents the male from getting away.
Toxoplasmosis mind controls mice and makes them seek out cats so they get eaten and the parasite can move on to the cat.
The hyena birth canal. If you think human childbirth is excruciating... you'd be right actually, we're pretty high up there on the list of animals with the worst birthing experiences, but hyenas have it even worse.
There's a parasite that goes into a fish's mouth, eats its tongue, and attaches itself to where the tongue used to be and essentially becomes the fish's tongue.
Hamsters eat some of their own offspring if they have too many to ensure they have enough resources to properly care for the rest.
Baby sharks try to kill and eat each other in the mother's uterus.

Til fish have tongues

Here’s some I know:

Dolphins rape other dolphins https://theconversation.com/dolphin-sexual-politics-gets-the-tabloid-treatment-6063
Praying mantis females often eat the head of males they have sex with. Some spiders do that too, like the appropriately named black widow spider. https://en.m.wikipedia.org/wiki/Sexual_cannibalism
Mass extinctions have occurred in the past, way before humans existed https://en.m.wikipedia.org/wiki/List_of_extinction_events
Genetic mutations often lead to inviable offspring or awful conditions (I don’t know specific examples off the top of my head)
Parasites can take control of insects and lead them to drown (also don’t know examples off the top of my head)

Beavers fuck up habitats and ecosystems about as much as humans used to before factories, which accelerated what we could fuck up. Beavers wreck shit up. Sometimes elephants do too, for that matter. And let’s be clear, the modifications these animals cause can have overall eventual benefits for an ecosystem, but they change the ecosystem extensively over a huge area, and any benefits you can ascribe to their actions could as easily be applied to human ecosystem modification too. “Oh yeah, the forest is completely gone, but now there’s new homes for different kinds of creatures that couldn’t live there before.” This sentence applies 100% to elephants, beavers, and yes, humans.

Some animals change their environment. We are one of them. Our tool use and brains allow us to do so on a pretty wide scale, but the destruction the elephants caused was pretty darn huge too. Humans also have the capacity to do with intention towards actively helping an ecosystem… elephants don’t have the ability for that kind of intentionality.

Of course, humans are also fully capable of acting without that intentionality too. It is pure coincidence that new ecosystems appear in the wake of elephant or beaver devastation— they weren’t actively trying to help other animals, they just wanted what they wanted. Our destruction can also have unintentional new ecosystems arise in our wake— the problem is that often we don’t LIKE the new ecosystems (bacteria and viruses, for example), and we often DO LIKE the stuff we destroyed.

But it’s not really different from what animals do. Because we aren’t separate from nature, we are nature. If we are bad, nature is bad. If nature is good, we are good. But this kind of binary thinking is too simplistic, life is more complicated than that, and we as humans have an ability to make value judgements and moral distinctions in a way that most animals cannot. We shouldn’t use that power in such a reductive way.

Predators eating prey alive, like lions eating bison from their bellies first.

Ouch. Looked it up. Its brutal. https://enviroliteracy.org/do-lions-eat-their-prey-alive/
TIL lions eat some prey alive because it saves the lions energy. They avoid spending too much energy killing a prey that is difficult to kill. Instead, they incapacitate (but not kill) a prey and start eating right away.

Malaria. Cholera. The black death. Syphilis. I could go on but you probably get the point...

I think there probably are some things that we could agree are universally disgusting , but it would still be a subjective opinion, just one that no one would argue. What I mean to say is that beauty and ugliness are human constructs, they don't actually exist. It would be kind of pointless to go back and forth with someone countering examples of beauty with examples of ugliness.

I agree that there’s a layer of human subjectivity in this whole discussion. Within that layer, I think it’s okay to get a gut sense that nature is brutal and grotesque. My goal is to avoid romanticizing nature.
Once we’re able to avoid our human bias of romanticizing nature, we can take the discussion to another layer, a layer that could be called more objective.
For example, we could talk about entropy and evolution’s attempts to fight against it. We could talk about evolution occurring at multiple scales and dimensions simultaneously, such as atomic structures, cells, and multicellular organisms. These are examples of assemblages, and they expand the possible behaviors of the parts. In other words, assemblages make the whole greater than the sum of the parts.
So, how does entropy, evolution, and assemblages connect with our discussion? Well, brutality and grotesqueness can usually be translated into the language of entropy and assemblages. Killing someone destroys an assemblage and increases entropy. Torture and trauma reduce the probability of an organism exhibiting variation in their behaviors. They reduce the emergent properties of the assemblage.
Is it always better to choose the language of entropy and assemblages over brutality and grotesqueness? No. Context matters. Again, if the goal is merely to avoid the romanticization of nature, the brutality and grotesqueness layer is appropriate.
- Definitely some interesting thoughts here. I do think you need to ask yourself if you aren't romanticizing in the opposite direction.

Pigs. Pigs take one generation to revert to feral state and are naturally pack hunting, intelligent, omnivores. Right now Texas and Florida is dealing with cases of hogs pulling apart horses to eat. There are cases where the hogs followed hunters home and trashed the place in retaliation.

It's a testament to our hubris that we've kept pigs and dogs for so long. Dogs won't recover, but pigs only need a year to come back for blood.

Cordyceps fungus. Prion diseases like Chronic Wasting Disease.

Both are horrible

Cordyceps fungus
Holy crap. This gave me the creeps. https://en.m.wikipedia.org/wiki/Ophiocordyceps_unilateralis This opened the door to the broader category of parasitoids https://en.m.wikipedia.org/wiki/Parasitoid
Prion diseases
Truly scary stuff. I vaguely knew that genetic problems are a thing, but I didn’t know the specifics. Thanks for sharing this https://en.m.wikipedia.org/wiki/Prion
There's currently a case being studied in the US south that looks like CWD jumped to humans.
- With RFK jr in charge of HHS we are probably doomed

Any documentary that talks about the life of insects and smaller animals is a horror film.

Dead and desiccated bodies around a body of water that has dried up. Fish, antelope, wildebeest, etc.

Also, I saw an eagle try to catch a snake once, and the snake was a constrictor. The snake wrapped itself around the eagle, grounding it. Neither were letting go, neither were going to survive. It was pretty metal, and it wasn't beautiful. Definitely grotesque and brutal.

A lot of other organisms will eat their young. Kinda messed up. Some apes try ripping each other's genitals off during fights. The insect world in general is pretty brutal tbh.

otters. baby otters. otters offering baby otters to be eaten first by predators.

Don't forget that adult otters are known to maul and rape baby otters for fun.

The insect world is a tiny nightmarish hellscape of armor, weapons, and sudden death.

Also, evolution isn't maximally efficient, it's just barely efficient enough. Eyes are a janky, often low-fi is good enough, affair. 99.9% of species that have ever existed are extinct. 99.9999999999% of species alive today do the bare friggin' minimum to throw DNA into either the wind or a hole and maaaaybe do nothing more than reproduce.

The Helicoprion existed.

Jellyfish. WTF?

First thing that comes to mind is reproduction/labor/birth. Especially ducks, otters, hyenas in no particular order of brutality. Add in spiders, preying mantis, angler fish.

Wild animals end up covered in ticks and sometimes even die from it

Tell them to look up how ducks, mate.

Ouch. Rape. Sometimes gang rape. Bloodied female. Sometimes drowned female. https://misfitanimals.com/ducks/how-do-ducks-mate/
Awful.

There have been a few significant mega-extinction events which have wiped out nearly every living thing on this earth.

Jeeze, I’m an outlier - my first thought was the beautiful spiral of a pine cone. Anything that has the Fibonacci spiral, but picking up a pine cone from a quiet, rain-soaked forest path where every footstep is cushioned by fallen needles and leaves. There are many types of cones, but the hard ones that have spread all their seeds form the most beautiful and uniform spirals. To a non-believer, it feels like one of the greatest arguments for the existence of an intelligent higher power

Pinecones are indeed beautiful. However, they are decidedly not one of the greatest arguments for the existence of an intelligent higher power. In fact, the whole claim about pinecones having the Fibonacci sequence is false https://youtu.be/1Jj-sJ78O6M
Additionally, I wouldn’t think that cones having nice shapes are an example of nature being brutal and grotesque. But I suppose you wanted to make the opposite argument: that nature is perfect and beautiful.

Some species of ants invade neighboring colonies and carry away larva to work as slaves.

https://en.wikipedia.org/wiki/Slave-making_ant