People are scratching their heads at this optical illusion that makes it look like this girl's leg is two very skinny legs.

Dr. VS Ramachandran once called the human's visual system a "bag of tricks." Although it might sound like a terribly reductive way to describe millions of years of evolution that formed such a complex way for human beings to perceive the world around them, it's hard to argue that he's wrong.

To prove that point, Ramachandran devised a super clever way of alleviating phantom limb pain for amputees using nothing but a box and mirrors. By tricking the mind into thinking their hand or foot is still there using one of these mirror boxes, patients could "itch" or "stretch" their missing limb and calm the nerve endings that don't know the limb is missing.

It was a super slick solution.

But that's because our vision doesn't always perceive what's actually there, and oftentimes, even when we see something clear as day, depending on how our mind is trained to process certain stimuli, we might see something entirely different than another individual.

Which is probably why we're so susceptible to optical illusions. Like this one that's currently got a ton of people on the internet doing a double take.

What started off as a simple fashion statement, turned into a bunch of people thinking that Twitter user Marisol had legs as thin as drinking straws.

And more than a few people thought this was the case.

Some compared her to Pixar superheroes.

While others mistook her for a beloved SpongeBob villain.

People immediately began referencing other popular optical illusions.

If you don't remember the dress, then let's take a little trip down memory lane.

What color is this dress to you?

How about these sneakers?

How about this picture?

What about this long-armed woman?

Or this room that'll turn you into a giant?

If optical illusions are your thing, check out some other cool ones here. I have to admit, though, there are few double-take worthy illusions that are as creepy as Daddy Long Legs girl here.

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