People all over the internet love to share what they consider fun facts. They’re all over the place, and yes, they’re often quite fun indeed.

What about NOT fun facts, though? Facts that make you uncomfortable, or make you think about stuff you’d rather not, et al?

If that’s more your think, we’ve got 16 of them right here.

16. Pretty metal.

When you get a sunburn, it’s actually your cells dying so they don’t get tumorous.

That is actually a fun fact, and pretty metal.

Cell gets DNA damage so it commits suicide so they don’t start overproducing and kill you.

15. How often do they clean the inside of a bus?

Bus seats are designed so that you cannot tell how dirty they really are.

14. Try not to worry.

The reason you’re supposed to contact a doctor if you have an erection lasting longer than four hours is because prolonged priapism can lead to gangrene of the dick. Blood goes in, deoxygenates, but can’t leave, so there’s no way for fresh oxygenated blood to come in, causing the tissue to turn black and die.

Don’t worry, though! This can be treated by using a big syringe to suck the trapped blood out.

13. The Japanese did some heinous crap.

During WW2, the Japanese built a human testing facility in China, which has come to be known as Unit 731. This was worse than a lot of concentration camps, but the people involved were never punished because the US granted them immunity and attempted to cover it up in exchange for access to their research. The Soviet Union attempted to try the people involved, and the US called it communist propaganda.

The test subjects involved prisoners, but also the homeless, the mentally disabled, and random Chinese civilians kidnapped from nearby towns, including pregnant women and infants.

Vivisections (cutting a person open with a T-shaped cut) were regularly performed, usually without anesthesia. Patients’ limbs were randomly removed and improperly reattached to see what would happen, and internal organs were also randomly taken. All without anesthesia, of course.

Prisoners were also injected with STDs (mainly syphilis) and then forced at gunpoint to rape other prisoners to spread the disease. Some of these prisoners included pregnant women, in which case they would either be vivisected live and have their fetuses removed, or the syphilis riddled babies would be born and eventually killed.

They also participated in biological warfare in several cities, usually by infecting fleas with paratyphoid and releasing them.

They tested any and all sorts of weapons on the prisoners, notably grenades and chemical bombs.

They also stuck people in pressure chambers until their eyeballs popped, spun people in centrifuges until they died, burned them alive, stuck people in gas chambers, injected them with random substances, and froze their limbs before breaking them off.

Most of the experiments had no practical application, and were done purely out of sadism. The Japanese government didn’t officially admit to this until 2003, and the US still actively denies it.

So yeah, have fun thinking about this. For more horrific war crimes committed by the Japanese, consider reading about The Rape of Nanking.

12. I don’t like this at all.

In the United States roughly 1/3 of all food is thrown away each year.

11. So, so sad.

There is a whale called 52 Blue that only sings at their frequency meaning it can’t communicate with other whales.

It is nicknamed the loneliest whale on the planet.

10. Horses are so fragile.

Horses can’t throw up.

So if they eat something bad or get a bad gas bubble, they just lay down and die.

One of the most expensive horses (10 Mil Euros) died because of a colic last December.

9. I do not like this.

your skeleton is w e t .

8. We just…lost them.

There are 8 unaccounted for American nukes and literally an unknown quantity of missing soviet nukes that range all the way from warheads to suitcase bombs.

theres a few lost in the oceans, theres a megaton yield bomb buried somewhere off the coast of georgia (state). and a couple in the Mediterranean

7. As someone who has gestated a human, this does not surprise me.

Your intestines will “wriggle” themselves back into the correct position.

Doctors who do any type of intestinal surgery don’t have to worry (too much) about how they put the intestines back in.

6. Just ignore it.

Valentine’s day is a holiday with one of the highest suicide rates.

More reason to convert it to cupcake and panty day. Anyone can enjoy those things, attached or not.

5. Biology is weird.

A certain type of angler fish reproduce via the male burrowing into the side of the female, eventually fusing.

The Male life is lost in the process.

4. Not the best way to go.

People who commit suicide by jumping off a bridge, those who don’t die from the impact, drown because the impact breaks enough bones that prevents them from swimming.

Poor bastard in my area died like this, took a bunch of pills slit his wrists, sat for a while in his bathroom and i guess decided it wasn’t fast enough so he walked down the road and jumped from a fairly tall bridge, the water below is pretty shallow but apparently he still drowned.

3. I couldn’t hate this more.

People who survived the Holocaust and get Alzheimer’s often think they are back in the camps.

So they escape one of humanity’s greatest horrors only to die in it 50 years latter.

2. Never go into the woods alone.

The FBI estimates there are between 25-50 active serial killers in the US at any given time.

1. Does it matter, though?

If you are an identical twin it is possible that you and your siblings identity’s were swapped and your parents never caught it.

Yeah, I definitely hate some of these y’all.

What’s your submission of a not fun fact? Drop it in the comments!