You've probably seen the terrifying nightmare fuel: a woman's face elongated into a beak, with bug eyes and stringy black hair.
You might have seen it shared on Facebook with a warning from parents or local police, accompanied by the scary story that some kids have been sent the image with a challenge to take drugs, hurt or even kill themselves. And you've seen coverage of those police warnings on NBC10 and other local news stations.
But is the Momo Challenge real? And is it something you need to be concerned about?
Under all the hype, it's hard to find any proof that the "challenge" is more than an urban legend. But that image has gotten plenty of attention, and it has frightened some kids.
In the latest round of coverage, some parents claimed on social media that Momo messages were being inserted into children's videos on YouTube, including Peppa Pig and Fortnite videos.
This led Kim Kardashian West to take to her Instagram story Tuesday with a plea asking YouTube to help. "Parents please be aware and very cautious of what your child watches on YouTube and KIDS YOUTUBE," she said.
Kardashian West's Instagram has more than 129 million followers. It didn't take long for YouTube to issue a response. The company said they had seen no evidence of the challenge on its site.
YouTube also noted that anything that encourages self-harm violates the platform's policies and "would be removed immediately."
The Atlantic and fact-checking website Snopes have both looked into the Momo challenge. They found no evidence that Momo pops up in Peppa Pig and found no evidence the Momo challenge has led anyone to harm themselves or to kill themselves.
Despite reports of suicides, the Today show reported that so far, no law enforcement officials have reported any injuries or deaths related to the so-called challenge.
But here's where things get complicated, especially for parents. Just as scary urban legends have spread at sleepovers long before the internet began (Bloody Mary, anyone?), the "Momo" image is something that many kids have heard about -- and may have seen.
NBC10 spoke to a young New Jersey boy who was sent the photo by a classmate. The Cape May Police Department had enough concerned parents reaching out that they posted a Facebook message to parents warning, "This 'game' is believed to be a way for people to hack accounts and is psychologically manipulative towards kids and teens."
Local police in Gloucester, Massachusetts posted a similar warning Tuesday. A mom in Lowell told the local NBC station that her 10-year-old had seen the image.
"I said, 'Evan, do you know who this is?'" the mom said. "And he said, 'Don’t show me. Don’t show me.' He knew exactly who it was. He had seen it before."
Just this week, Today interviewed a mom who said her three-year-old knew that Momo was the "scary lady" with "big eyes, long black hair and a white face."
The Momo image is actually a cropped photo of a sculpture created by the artist Keisuke Aisawa for Japanese special-effects company Link Factory, the Atlantic reported. It's called "Mother Bird" and was displayed at a Tokyo gallery that specializes in horror art in 2016.
Someone snapped photos for Instagram, a Reddit called "Creepy" picked them up -- and Momo was born, ready to alarm parents and get shared around by teens.
Even if Momo is more viral than vicious, the picture can be scary.
Meghan Walls, a pediatric psychologist, told NBC10 that parents should take preemptive action and gently ask their younger children if they know about the image.
"Say something like, 'There's some scary things that pop up on phones and tablets, and if you ever see something like that, come get me,'" Walls said.