Take allergies, for example. Our immune system, which usually protects us from threats like bacteria, viruses, and parasites, can suddenly decide that a random thing we encountered is dangerous and trying to kill us.

That peanut butter you just accidentally touched: totally trying to kill you (at least, a person who is allergic to peanuts' immune system thinks it is).

It's not that the substance is actually harming the body, but the immune system recognizes it as a pathogen and tries to attack it. This can result in unpleasant symptoms like hives, diarrhea and vomiting, difficulty breathing, and even anaphylaxis.

So yeah, our bodies are fascinating and complex, but they're definitely far from perfect.

Reddit user u/RustyUnicorn wanted to know more about these odder things about the human body, so they asked:

"What's the most unsettling fact about our bodies?"

Be forewarned: some of these are a bit gross.

10.

A brain aneurysm can happen at anytime, regardless of heatlth, that will cause instantaneous death. There are nearly no prior symptoms for detection. So you could just die at any moment in your life and there is nothing to warn you of it.

-pingupingupingupingu

My professor called them "death's ninjas" and I can honestly never stop seeing them that way.

You can be making a sandwich, and bam, you're dead before you hit the ground.

-murrimabutterfly

9.

The digestive tract extends from your mouth to your anus. In other words, you have a hole through you. You're a doughnut.

-Daemori

8.

Grinding your teeth can put up to 900 lbs of pressure (psi) on your teeth (especially those who are night grinders). That’s like the pressure of 10 5th graders standing on your teeth. Please get a mouth guard if you grind your teeth at night. Save your teeth and your money. (Source: I'm a dental school student)

-shantell295

7.

Some of your ligaments are so strong that they'll break your ankle before they get damaged themselves.

-betak_

6.

Happened to me. Broke my ankle - but what really happened is the ligament ripped a piece of bone off. Imagine attaching a toilet plunger to the wall - and then pulling on it so hard that a big chunk of wall just ripped right off. That’s what happened to my ankle.

-Lars_lars_lars

5.

You are less of a single animal and more of a super organism. The average human body has more bacteria than somatic cells. You are actually thousands of different organisms working together.

Next time you're feeling down, let this remind you just how incredible you are.

-Graggle1

You're never alone! You've got a bunch of microscopic little buddies with you!

-Spotellis

4.

The sense of smell requires physically touching molecules (unlike audio/vision, which are waves).

That means that when you smell someone's fart, something that was inside their colon is now inside your nose. Little bits of their poop are inside of your head.

-frnoss

3.

If the lining in stomach disappeared, you would digest yourself.

-texturedtie

2.

Cancer happens when a cell goes rogue and refuses to destroy itself on schedule. Then when it multiplies, the new cells don't destroy themselves either. Soon there's a massive tumor whose only crime was not wanting to die. Unfortunately, that s**t kills the whole body.

This is why cancer is so difficult to cure. It's not some foreign invader. It's your own cells just doing their own thing instead of functioning as a unit.

-thudly

1.

There are things rotting and decaying inside you right now. Some of those things are, in fact, You.

-Anonymal13