The scientific reason this viral illusion tricks your brain into seeing colours that don’t exist

My head hurts

1 hour ago

Kieran Galpin | Trends

Comedian and magician Pete Firman broke the internet earlier this week when he posted an optical illusion involving a green pig and a pink frog.

“I can make you see colours that don’t exist!” he said in a Twitter post that’s since been viewed an insane 33 million times.

In the video, Pete said: “I can make you see colours that don’t exist. Look at this image. You’ll see that both of the animals are the wrong colours.”

In the image, the pig is green, and the frog is pink when, obviously, it should be the other way around. Pete urged viewers to stare at the “X” in the middle of the screen before he drained away all of the colour. Though I was sceptical at first, it actually worked, and the pig was pink, and the frog was green. Mind officially BLOWN.

I can make you see colours that don’t exist! pic.twitter.com/MRRXg1c9hH

— Pete Firman (@petefirman) August 19, 2026

People were pretty stunned in the comments, as one person wrote: “What is dis wizardry?!!!”

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“Man, hell nah, wtf are our eyes,” another said, as a third added, “How the f*ck does this work. Do the colours get inverted because your brain knows the colours of the animals were wrong???”

So, how does it work? Is Pete Firman a legit sorcerer, or is there a scientific explanation? It’s the latter, but just as magical.

Science can explain Pete Firman’s illusion

The optical illusion has gone super viral on Pete Firman’s Twitter, but it’s not actually the first time it’s popped up on the internet. It’s been shared before, including in 2025 on TikTok.

But as it turns out, there’s no magic involved. You see, by staring at the cross for an extended period of time, you tire out the receptors associated with those specific wavelengths. In this case, it’s the cone-shaped cells that pick up the pink and green that are flipped, making the animals the correct colours. So, so cool.

Grok somewhat explained: “It’s a classic negative afterimage illusion. You stare at the green pig and purple frog (plus the black cross) long enough for the cone cells in your eyes to fatigue on those specific wavelengths.

“When the colours vanish, and only the black outlines remain on white, the fatigued cones under-respond. Your brain interprets the imbalance as the complementary colours: pinkish for the pig and greenish for the frog. Those hues aren’t on the screen at that moment; your visual system invents them.”

Cool is an understatement.

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Featured image credit: X