Brainstorm or green needle? What do you hear?

The ‘Yanny/Laurel’ audio illusion may have taken the world by storm earlier this week, but attention is already turning to a second mysterious sound bite that has listeners scratching their heads.

Like the Yanny/Laurel debate, this new illusion has also divided public opinion as to what words are being heard.

In the video, a children’s figurine plays a recorded message. But is it saying “brainstorm” or “green needle”?

The bizarre twist with this video is that most viewers have the ability to switch between the words, depending on which one they are thinking of.

Other variations of the recording include “brain needle” and “green storm”.

YouTube users were fascinated by the illusion, with many finding it more impressive than the Yanny/Laurel mystery.

The figurine is a character named ‘Brainstorm’ from the children’s television series, Ben 10. Source: YouTube/CheddarCheese

“This is amazing,” one man wrote. “Yanny Laurel is nothing compared to this one. It goes from three syllables to two?!”

“I can switch between brainstorm and green needle easily,” another user said. “Unlike laurel and yanny. All I hear is laurel.”

In an interview with HuffPost UK, Professor Valerie Hazan, a speech, hearing and phonetic sciences expert from University College London, was able to offer an explanation for these unusual audio illusions.

On explaining how you can switch between hearing both words, Professor Hazan said: “The reason that a person can see their perception switch without explanation may also mean that our ears and brain have latched on to the other acoustic pattern than the one they were previously latching on to.”

And if you’re wondering what the figurine is really saying, it’s “Brainstorm”.

The toy is a character from the popular children’s cartoon series Ben 10, whose name is Brainstorm.