Endless Thread

Lagoa Misteriosa, or Mysterious Lagoon, is located near the small Brazilian city of Jardim. Surrounded by lush jungle, the surface of the lagoon looks like azurite — still as glass and crystalline. Its waters are so clear, looking down you might expect to see the bottom, except... the bottom of Lagoa Misteriosa has never been found.

Today on Endless Dread, our annual witch's hat tip to spooky season, Amory takes Ben deep down into the story, and mystery, of Lagoa Misteriosa. The story for Amory began on Reddit in r/thalassophia, a community devoted to the fear of deep water.

Show notes:

The bottom of this lake has never been found (Reddit)

Lagoa Misteriosa

Footage of Misteriosa (Lagoa Misteriosa on Instagram)

Divers Have Descended More Than 220 Meters Into This Brazilian Lagoon — And Still Haven’t Found The Bottom (Daily Dot)

Dave Not Coming Back | FULL DOCUMENTARY (YouTube)

This content was originally created for audio. An auto-generated transcript is available on Apple Podcasts and Spotify. Heads up that some elements (i.e. music, sound effects, tone) are harder to translate to text.

Up to a billion people use ChatGPT every week, for everything from the mundane to the weird to the deeply personal. It is commonly assumed that these messages are private – between the user and the LLM. It is commonly assumed that these messages are private – between the user and the LLM. But in some cases, human reviewers are reading these conversations and offering editorial feedback to help ChatGPT sound more human.

Reporter Joseph Cox of 404 Media broke the story of Project Lily, Open AI's initiative to use human reviewers to train and improve ChatGPT. He breaks it down for us on this week's Endless Thread.

Show notes:

Inside ‘Project Lily’: The Humans Reading Your ChatGPT Chats
(404 Media)

This episode was produced by Grace Tatter and Frannie Monahan. It was co-hosted by Grace Tatter, Ben Brock Johnson, and Amory Sivertson, and edited by Dave Shaw. Mix and sound design by Paul Vaitkus.

"Should I be joking at a time like this?"

That's the question then 33-year-old Brooke Eby asked herself when she uploaded her first piece of TikTok comedy in 2022, about being diagnosed with a terminal illness. Brooke built an audience of hundreds of thousands of people who were rooting for, and laughing with, her. Sometimes it got weird.

Brooke died due to complications with ALS earlier this month. She was 37.

In 2025, she talked to Endless Thread hosts Ben Brock Johnson and Amory Sivertson about how facing death changed her relationship with social media and online community.
Show notes:

Brooke Eby's TikTok, Instagram, and YouTube

ALSTogether

When Your Terminal Illness Makes You a TikTok Star (The New York Times)

This episoded was written and produced by Grace Tatter. It was co-hosted by Ben Brock Johnson and Amory Sivertson. Mix and sound design by Emily Jankowski.

The internet is the great connector. Talk with nearly anyone at any time about anything. But that kind of freedom can lead to misunderstandings. Maybe your neighbors discover your cruder, less friendly persona online. Maybe a debate over holiday lore becomes a battle front.

Endless Thread producers Grace Tatter and Frannie Monahan bring two stories to remind us that the internet is a morass of information that no one can ever control.

Show notes:

"How I became the villain of El Cerrito’s Nextdoor" (Oakland Review of Books)

Bomellida FAQ (GitHub)

This content was originally created for audio. An auto-generated transcript is available on Apple Podcasts and Spotify. Heads up that some elements (i.e. music, sound effects, tone) are harder to translate to text.

Get out your graphing calculators, because today's episode of Endless Thread is about a math problem.

Specifically: wt(π1, . . . , πm) = m−1 ∑ i=1 wt(πi , πi+1)

Now, pencils down. Stumped? So were mathematicians for decades. That is, until the equation was solved in a thread on 4Chan about watching the anime The Melancholy of Haruhi Suzumiya. 

Show notes:

A lower bound on the length of the shortest superpattern (oeis.org)

Sa-Shi-Su-Se-So: The Secret of Japanese Cooking Basics (Umami Insider)

This content was originally created for audio. An auto-generated transcript is available on Apple Podcasts and Spotify. Heads up that some elements (i.e. music, sound effects, tone) are harder to translate to text.