People make 'unnerving discovery' after staring at optical illusion for a few seconds

Optical illusions appear different to different people (stock) (Image: Getty)

An optical illusion on TikTok has left viewers spooked and intrigued in equal measure.

Optical illusions, drawing on colours, light, and patterns, trick the viewer into seeing images differently from reality.

This fascination is heightened by the fact people experience these pictures distinctively, with some unable to spot the illusions at all, offering a glimpse into the complex collaboration between our eyes and brain.

A particular illusion posted by Magic Eye Guy on TikTok has created quite the stir online - for some, it's sheer fascination; for others, it tiptoes into the eerie.

To an unsuspecting eye, the viral image seems to be nothing more than a colourful assortment of shells. But there's more to it.

With a voiceover teaching viewers how to see the hidden 3D image, the post instructs: "Wait, this isn’t just a picture, it’s a stereogram - let me teach you how to view it. Turn the screen sideways, hold it close to your face, and slowly move it away while not focusing and a 3D image should appear." Stereograms are flat pictures that reveal three-dimensional scenes when observed correctly.

Social media users were quick to dive into the comments section of the post, eager to share their experiences.

One individual exclaimed: "I finally saw something!! I still couldn't tell what it was but, I saw it!" Another shared their shock: "THAT WAS TERRIFYING IT WOULDN'T GO AWAY," and yet another said: "This is the first stereogram that I’ve been able to see."

Another asked for guidance: "Help! Where do I focus? In the middle? In the corners? up? Down? I just can’t," prompting a response from the creator: "You don’t focus. Your eyes need to fix on two separate places but you can’t do that by trying to focus. Relax your eyes and stare through the image and they should separate."

Others were quick to describe the image they deciphered after heeding the advice of the original poster. One user said: "A fish jumping out of a hoop and a seal about to eat it." Another said: "Big something trying to eat the little fish," which earned a congratulatory "well done" from the original poster.