The internet is a weird place. Like, really weird. Sure, you can order socks at 3am or find a recipe that uses four kinds of cheese and zero judgment. But it’s also full of digital rabbit holes so strange they’ll keep you up at night. These aren’t your usual Reddit threads. These are the ones that stick in your brain like gum in carpet. So here you go. Ten creepy internet mysteries that still haven’t been solved. Proceed with caution.

1. The Markovian Parallax Denigrate Back in 1996, a bunch of bizarre, nonsensical messages started flooding Usenet groups. They had titles like “Markovian parallax denigrate” and were full of random words that made no sense together. No one knows who posted them or why. Some people think it was early spam. Others think it was a coded message. Or a bot that got loose. Either way, the internet’s never really figured it out.

2. A858 This Reddit account started posting long strings of what looked like random code in 2011. For years, no one could figure it out. A few of the messages got cracked, but most remained a total mystery. Then in 2016, the account just stopped posting. No explanation. Still gives people the creeps.

3. Cicada 3301 Maybe the most famous internet puzzle ever. Starting in 2012, a group calling itself Cicada 3301 posted mind-bending riddles across forums, websites, even physical locations around the world. Some people solved parts of it. Most didn’t. No one knows who was behind it. NSA recruitment test? Cult? ARG? Nobody knows. Still haunts Reddit.

4. Lake City Quiet Pills This one started on Reddit too. A user who went by the name religionofpeace died, and users noticed some weird stuff in their post history. It led to a bizarre site called Lake City Quiet Pills that looked like a crude image host—but the code behind it hinted at possible assassination jobs. It’s unclear if it was real or just an elaborate troll, but either way, very unsettling.

5. The Plague Doctor Video In 2015, a super creepy video started circulating. It showed someone in a plague doctor outfit sending what looked like encrypted messages through flashing lights and sound patterns. The footage was deeply unnerving. Some people thought it was a promo for a game. Others thought it was a threat. Still not officially explained.

6. Webdriver Torso A YouTube account started uploading thousands of short videos showing colored rectangles and electronic beeps. People thought it was a spy code. Turns out it was Google testing video quality—but the weird vibe and secrecy around it made it legendary. Also, one of the videos randomly showed the Eiffel Tower. Nobody knows why.

7. The Mystery of 11B-X-1371 Another creepy video, this one showed up in a forest in Poland and involved someone in a mask making strange hand signs. There were Morse code messages, sound spectrograms with hidden images, and a whole bunch of symbols. Some of it got decoded. Most didn’t. It’s still nightmare fuel.

8. I am Sophie This one started on YouTube too. It looked like a vlog from a rich influencer named Sophie. But things got weird fast. Glitches, dark turns, distorted footage. Turned out to be an art project, but it blurred the line between fiction and reality so well that it freaked people out for weeks.

9. The Publius Enigma Back in 1994, someone calling themselves “Publius” started posting cryptic messages on Pink Floyd fan forums, claiming there was a hidden puzzle within the album The Division Bell. Pink Floyd never confirmed it. Fans are still arguing about it. Was it real? A hoax? Just someone bored and clever? Still unclear.

10. Missing Pages from the Voynich Manuscript Online Everyone knows the Voynich Manuscript is weird. But someone once claimed to have found scanned pages online that aren’t in the original physical copy. Then they vanished. Some say it was fake. Others swear they saw it. If true, it means we might be missing even more of this book that already makes zero sense.

So yeah. Sleep tight. The internet remembers everything—even the creepy stuff we can’t explain. Yet.