There’s honestly no better feeling than collapsing into bed after a long, exhausting day—your head hits the pillow, and before you know it, you’re off in dreamland.

But waking up? That’s a different story. Nothing kills the morning vibe faster than stumbling to the mirror and spotting that weird, yellowish gunk stuck in the corners of your eyes.

Most of us are so used to it that we just wipe it away and move on, pretending our bodies aren’t doing totally gross stuff while we sleep. But ever wonder what that “eye crust” actually is?

Well, after a TikTok video went viral breaking it down, people were seriously stunned.

“If you have ever woken up in the morning and you have some crust on your eyes,” explains Andrew Huberman in the video, “And you know that crust, that kind of yellowy stuff—sometimes it’s yellow, I know this is kind of gross.”

He goes on: “That’s actually dead bacteria that your eyes have successfully defeated during your night’s sleep.

“So when you wipe those away, you’re taking the casualties of a war that you won during your night’s sleep and you’re whisking those away.”

Yep, you read that right—your eye gunk is basically your body’s little victory trophy from a microscopic battle that happened while you were snoozing.

During sleep, your eyes still produce small amounts of oils and mucus to stay lubricated. But since you’re not blinking overnight, the discharge doesn’t get washed away like it usually would and instead gathers in the corners.

This eye goop can show up in all sorts of forms: crusty, sticky, thick, thin, white, clear, or a shade of yellow.

Naturally, TikTok users had thoughts.

One person wrote: “I refuse to lose even when I’m sleeping.” Another chimed in with, “Starting the day with a victory.” And then there was someone who dropped this little bombshell: “When I was in kindergar[t]en I put them in my tea,” complete with a skull emoji. Honestly… we don’t even know where to begin with that one.

For the most part, eye discharge is completely normal and nothing to stress over. But if your eyes are producing a lot of thick, sticky yellow pus, especially if it’s clinging to your lashes, it could be a sign of conjunctivitis (aka pink eye).

This condition is usually caused by an infection or allergies. While it tends to clear up on its own in a week or two, it’s far from pleasant—bringing redness, itching, burning, a gritty sensation, and that signature goopy pus.

To ease symptoms, the NHS recommends a few simple steps:

• Gently clean your eyelids with boiled (and cooled) water using a clean cotton wool pad—one pad per eye.
• Place a cold flannel over your eyes for a few minutes to help soothe the irritation.