If you've ever seen one of Dr Sandra Lee's notoriously disgusting clips, you'll know how strangely mesmerising they can be.
Dr Lee, also known as "Dr Pimple Popper", has gained a cult following in recent years thanks to her gruesome — and insanely popular — videos of pimples, cysts and boils being squeezed.
The US dermatologist kicked off her unusual form of fame after posting a straightforward blackhead extraction on social media three years ago, news.com.au reports.
People couldn't seem to get enough, and she quickly realised there was a niche market for her footage.
Today the 47-year-old YouTube star has amassed millions of subscribers on her channel, which grows by thousands every single day and has already attracted 2.5 billion views so far.
She also has more than four million social media followers, has made guest appearances on several TV programs and has launched her own skincare range, SLMD Skincare Products, for people with issues such as acne.
She's also collaborated with board game company Spin Master to create a game called Pimple Pete, which is similar to the classic Operation, and last month the Dr Pimple Popper TV series launched in the US.
According to The Sun, Dr Lee is believed to now be worth a staggering $9.2 million, with her YouTube channel raking in around $4350 every day.
Dr Lee, who built up her following by offering free treatment in exchange for patients allowing her to film and share their procedures, told The Sun there was "a subculture of people on the internet" who loved sharing popping videos with each other.
She said viewers were first fascinated by the gory films, but were also intrigued by the patients' transformation.
"I think initially some people might watch it because it's like a car accident — you can't look away," she told the publication.
"But I think people stay because they then feel like, 'This is really nice what has happened with this person.'
"I'm very proud of these patients because it takes a lot of guts to show the world, especially when it's been hidden."
She also spoke about the challenges of treating extreme cases.
"I'm not squeamish but a lot of these cysts in particular can have an odour that's not very nice," she said.
"I train myself not to be grossed out by it because I don't want my patients to feel uncomfortable or embarrassed.
"If someone was doing something on you and all of a sudden said, 'Oh my god this stinks, it's disgusting,' you would feel really bad, so I really want to make sure my patients know that I am not judging them in any way."
Dr Lee said most of the cases she saw were preventable, and that many came down to genetics and a patient's skin type.
Over the years, Dr Lee said she had treated some particularly memorable cases, including "people who have something growing on the middle of their forehead the size of a golf ball, or people who have something growing out the back of their neck the size of a large grapefruit or even a bowling ball".
One of those included "The Unicorn" — a man who had been living with a "huge golf-ball sized cyst" in the middle of his forehead for years.
She said patients with such extreme skin problems suffered emotionally as well as physically.
Dr Lee also urged people to get professional help as soon as possible, and to never pick at a pimple or cyst, as it "increases your risk for scarring".
"That's a badge you will wear for the rest of your life," she said.