A simple wool hat is taking TikTok by storm as users are left astounded by the cap’s astonishing color-changing optical illusion.

First came the white-gold, blue-black dress debate. Then followed the viral waist-cinching optical illusion dress that took over TikTok (not to mention the auditory ‘Yanny’ vs ‘Laurel’ chaos).

Now, another article of clothing is taking over the internet, and it’s confounding TikTokers with its near-unbelievable color changing abilities.

On November 18, environment designer Otelia Carmen uploaded a video to the platform showing off her new winter hat. It’s a simple article of clothing — a basic winter beanie with a puff of faux fur on top.

TikToker Otelia Carmen is taking the internet by storm thanks to her viral winter hat.

Color-changing winter hat goes viral on TikTok

However, the actual color of the hat is causing some debate online. Carmen was shocked to see that the hat, which she had initially thought was green, had mysteriously changed colors when she brought it home.

Her TikTok taking the hat through different rooms in her house has gone viral, showing the beanie changing from brown to red to green.

Carmen chalks up this incredible anomaly to “metamerism,” a phenomenon where the color of two different objects can appear to be the same under a certain light source.

@oteliacarmenWhy lighting should be just as important as color/material selections!! ##interiordesign ##learnontiktok ##designertips ##colortheory ##shopwithme♬ Do It To It – ACRAZE

To prove that she wasn’t applying a filter, the designer moved from room to room inside her home while wearing the cap without cutting away — and sure enough, the cap changed colors from brown to red to green again.

The internet’s collective mind has been blown by this jaw-dropping hat, with some users in the comments refusing to believe the optical illusion is real, while others want to know what material the hat is made out of.

@oteliacarmenReply to @nb_1776 Room by room, no filters, mirror reflections for extra credit 😅 ##colortheory ##metamerism ##interiordesign ##STEMtok♬ One Right Now – Post Malone & The Weeknd

This phenomenon is similar to the white/blue dress from 2015, which scientists concluded was caused by a “confusion” between the kinds of light hitting the dress and how our brains process that information.

Thus far, Carmen’s videos showing off her magical hat have garnered millions of views in the span of a single day. The TikToker claims that she picked up the viral cap at MARC’S — and we’re certain they’ll be seeing an influx of customers hoping to try out the hat for themselves.

ncG1vNJzZmivp6x7pbHXnqmtp16YvK57xKernqqklravucSnq2iumaeurXnWqKalZZiWwW65xKyknqqZr7K0edOioq2nm2LCtLHRrGSwoaSdeqS7y6ipZpuYlruotc2gZKiopJ6woriMoqOlraOevK95kHBnbGhgaXw%3D