15 Facts You’ll Wish You Had Never Learned

From the parasites that call your face home to what really makes your eyes red in public pools to literally everything about anglerfish sex, these fascinating facts are ones you’ll wish you’d never learned, adapted from an episode of The List Show on YouTube. Don’t say we didn’t warn you!

1. Regulators allow certain amounts of nasty stuff in food products.

Powerful as it is, the FDA can’t keep every single cockroach leg out of your lunch. Instead, it decides on safe proportions of nasty stuff to allow in certain food products.

Every 500 grams of canned tomatoes, for example, can legally harbor about 10 fruit fly eggs or two maggots. Some mixing and matching is fine, too, so a manufacturer could technically toss in five eggs and one maggot without the FDA knocking on the factory door. An average of 225 insect fragments can make it into each 225 grams of pasta. A 225-gram box of raw pasta can also have roughly 4.5 rodent hairs in it. A 100-pound bag of shelled peanuts can contain 20 whole insects. A pound of cocoa beans can have 10 milligrams of “mammalian excreta.” 

Will all these unsavory substances in your food kill you? No. And to be fair, the numbers above are all legal maximums—if a company is consistently churning out boxes of pasta with 224 insect fragments inside, the FDA is probably going to step in.  

2. It’s not the chlorine in the pool that irritates your eyes.

When your eyes get red and irritated after swimming in a public pool, you probably assume chlorine is the culprit. Instead, you should be blaming all the people who peed in the pool. 

The nitrogen in urine mixes with chlorine to create a compound called chloramine—and that’s what bothers your eyeballs. Chloramine is also what gives pools that classic chlorine odor. So if your neighborhood pool reeks of chemicals, it’s probably just brimming with pee.

3. Fetuses drink their own urine ...

Speaking of pee, you spent a good five or six months drinking yours. Around week 13 of development, fetuses have fully functioning kidneys that filter urine into the amniotic fluid … which they then drink. 

4. … and are covered in a “waxy, cheese-like substance.”

It’s not the only off-putting element of dinner in the womb. Fetuses also grow a very fine layer of downy hair known as lanugo. This helps bind their skin to a white protective coating called the vernix caseosa. Just to complete the mental picture, Healthline describes it as a “waxy, cheese-like substance.” In Latin, the term essentially means “cheesy varnish.”

Though babies are often born with some vernix and lanugo left on them, they start to shed both in the weeks before their due date. It all ends up floating in the amniotic fluid, where it, too, becomes baby food. And you thought pureed peas were gross.

5. Teratomas can contain muscle, bone, hair, and teeth.

A teratoma, like other tumors, is an errant cluster of tissue that can be benign or malignant. But this isn’t just a garden-variety lump. Teratomas can contain bone, muscle, hair, and even teeth. 

Teratomas are made up of germ cells, a.k.a. reproductive cells. And while they can technically develop anywhere, they’re most often found in reproductive organs like the ovaries and testes. Tailbones are another common location.

6. Disney parks are a popular, not-so-permanent resting place.

Disneyland’s Haunted Mansion isn’t just home to make-believe members of the undead. It’s also played host to quite a few actual dead people—their ashes, at least. Disney parks are an extremely popular place for people to scatter their loved ones’ remains, and the Haunted Mansion tops the list of hot spots. As one Disneyland employee told The Wall Street Journal in 2018, “The Haunted Mansion probably has so much human ashes in it that it’s not even funny.”

For the record, sprinkling human ashes on Disney grounds is prohibited, and custodians grab the vacuum whenever they see any. The code for that task is “HEPA cleanup,” after the especially strong filter used while sucking them up. So the next time you see a sooty patch outside Sleeping Beauty castle, just know that it’s not because Bert the chimney sweep stopped by.

7. Six vials of smallpox were found in an FDA storeroom.

In 1980, the World Health Organization announced that smallpox was officially gone from the globe. Natural cases no longer occurred, and all research labs that had samples of the smallpox virus had to destroy them. Specimens were preserved in only two places: the CDC’s lab in Atlanta, and another high-security facility in Russia.

So, you can imagine everyone’s horror when, in 2014, six vials of the smallpox virus were unearthed in an FDA lab in Maryland. They weren’t exactly kept under lock and key, either—they were just sitting in a box in an old storeroom. 

The samples reportedly dated back to around the 1950s, when everyone was playing it a little faster and looser with certain deadly substances. With the help of the FBI, the vials were transferred to the CDC’s Atlanta location and installed in a level four biosafety lab—the highest level there is. As NPR science correspondent Geoff Brumfiel explained at the time, “That’s the kind of lab where people are wearing moon suits.”

8. Thawing permafrost could unlock a host of problems.

In 2020, NASA and the European Space Agency launched an initiative to study how the deterioration of Arctic permafrost might affect global methane levels. But researchers found that this thick layer of frozen ground may not just unlock methane as it melts. As the ESA reported in 2021, it also “has the potential to release antibiotic-resistant bacteria, undiscovered viruses and even radioactive waste from Cold War nuclear reactors and submarines.” 

9. Most cruise ships have a morgue below decks.

The next time you set sail for the Caribbean on a luxurious cruise, try not to think about the morgue belowdecks. Most cruise ships have one, along with body bags, in case a passenger passes away on board.

Morbid as it is, things would definitely be worse if ships had nowhere to store a corpse. According to one urban legend, chefs would serve heaping helpings of ice cream to diners whenever someone died—not as a consolation gesture, but because they needed to empty a freezer so that there was somewhere cold to preserve the body.

While an impromptu ice cream doesn’t actually spell death, “Operation Rising Star” actually does. That’s the term some cruise officials use to let other employees know that someone just died. If you hear “Operation Bright Star,” someone’s in the midst of a serious medical emergency. 

10. Anesthesia awareness affects about .15 percent of general anesthesia patients.

Anesthesia awareness, also called unintended intraoperative awareness, is a phenomenon as self-explanatory as it is scary. Basically, you’re anesthetized for surgery, but then you wake up—to some degree—during the procedure. 

Before you get too freaked out, it’s pretty rare. According to the American Society of Anesthesiologists, it’s thought to occur in only about one to two of every 1000 procedures that require general anesthesia. Moreover, it’s often completely painless, and some patients are only vaguely aware of what’s going on. 

That said, there have been some horror stories. In 2008, 44-year-old Canada native Donna Penner was about 10 minutes into a laparoscopy when she suddenly awoke on the table. As she told the Associated Press, “The next thing I heard was the surgeon speak up and ask for the scalpel. I felt him make the first incision into my abdomen.”

While the general anesthetic clearly hadn’t done its job, the paralytic drugs had. So not only was Penner in excruciating pain, but she couldn’t alert anyone. In her words, “I couldn’t even move my eyes back and forth … I tried to make tears. … I wanted to scream. I tried to scream.” She described the pain as “pure torture.” Penner even claims she had an out-of-body experience in order to cope.  

12. A real-life Finding Nemo situation would end differently.

Everybody knows that Disney/Pixar’s Finding Nemo isn’t exactly accurate. Fish don’t speak English, sea turtles don’t act like surfers, and pelicans generally don’t help marine animals escape from dentist offices.

It’s probably a good thing that the filmmakers used some artistic license. If the story were a true reflection of aquatic life, the heartwarming bond between Nemo and his father would have developed a little differently. 

In reality, when a dominant female clownfish dies, the dominant male becomes a female and reproduces with the largest male in the group. So here’s what would have happened after that barracuda took out Nemo’s mother, as explained by fisheries scientist Patrick Cooney: “His father transforms into a female now that his female mate is dead. Since Nemo is the only other clownfish around, he becomes a male and mates with his father (who is now a female).”

13. Some anglerfish species have serious attachment issues.

In certain species of deep-sea anglerfish, the much smaller male bites into the side of a female and never lets go. His body becomes part of hers, and since he no longer needs to see or swim, his eyes and fins begin to disappear. After a while, he looks less like a fish and more like a fleshy protrusion. But he’s not dead: His mate feeds him nutrients through their now-connected blood vessels, and in return he supplies her with sperm. 

14. Your face is covered in parasites.

Before you grimace at the male anglerfish’s parasitic existence, you should know that you have parasites, too. One particular kind lives on your face—or, more specifically, in the hair follicles on your face.  

These scaly, eight-legged critters are called Demodex mites, and they’re known for gobbling down oil and skin cells that end up in your follicles. Their life cycle is only a few weeks long, but don’t worry—they make good use of their brief time on Earth/you, crawling on your skin while you’re asleep.

It gets worse. Demodex mites lack anuses or any other way to get rid of waste. So they just store it all inside their bodies and let it spill out after they die and start decomposing. That waste did come from your skin in the first place, if it makes you feel any better.

15. Everything you smell involves molecules getting inside your nose.

Let’s end on a slightly less disgusting note. When you smell something, it’s because odor molecules from that thing are actually getting in your nose. Fresh-baked cookies? Yes. Puke? Poop? Putrid meat? Also yes. Perhaps slightly less disgusting, but still gross.

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