Karina Garcia is known as the internet's "slime queen" — and that's a big compliment. In less than three years, the 23-year-old has turned her one-time hobby — posting DIY slime videos to YouTube — into a full-time career, and gone from waitressing to making millions. For those who don't know, slime — the kind Garcia whips up — is no longer something you dig out of a clogged drain. It's a puffy, viscous, often pastel-colored craft that you can make at home using Elmer's glue, water, 20 Mule Team Borax and the instructions of one of the internet's growing cadre of YouTube slime stars.

Photo courtesy of Karina Garcia

Garcia's YouTube page has more than 200 videos, demonstrating everything from how to make a $1,000 slime smoothie, to edible snow slime, to slime balloons and even slime bubblegum. Her channel has more than seven million subscribers and her videos have collectively garnered more than 900 million views. "I always knew what success was and I always wanted to be successful, but I've never dreamed of having this much success," she tells CNBC Make It. Garcia grew up in California as one of six children. She describes herself as an "arts and crafts kid" who loved everything beauty-related. One day, after she'd created a lipstick using a mixture of old eye shadow, chapstick and clear lip gloss, her twin sister encouraged her to film the process and upload the video to YouTube. She posted her first video, "Easy DIY Lipsticks!" in February 2015. After that, she started posting weekly videos on beauty-related crafts, like how to make makeup brush holders. She was browsing Pinterest for more crafting ideas when she came across a simple recipe for homemade slime. "This was the most basic slime ever," she says. "I started throwing random stuff in it to make different textures." In August 2015, she uploaded her first slime video, showing how to make squishy, slime-textured soap out of Herbal Essences shampoo, corn starch, cooking oil and soap dye she found on Amazon. After that, though she still posted the occasional beauty tutorials, her regular video uploads were mostly focused on variations of slime. Producing the videos started as a hobby but grew into a side hustle for the California native. She was working as a waitress for her older brother, who was a wedding coordinator, but after growing a large enough following to bring in advertising money from her videos, she quit her job to focus on making slime, full-time.

Photo courtesy of Karina Garcia

Today, a search for "slime" on YouTube yields more than 20 million results, but at the time, content like Garcia's was rare, and she got in on the ground floor of the sticky business. "My first check from YouTube was only like $50, but then it kept getting bigger," says Garcia. "The paycheck that was like super crazy to me was when I got a $10,000 check. That was when I felt like I made it." Garcia received that check less than a year after uploading her first video. YouTube declined to comment on Garcia's earnings, but Danny Fratella of Social Blade, a data company that tracks estimated earnings and future projections of YouTube stars, estimated that Garcia likely earns anywhere from $80,000 to $160,000 a month on ad revenue alone. "She has over 960 million total views on her channel, which have likely paid out several million dollars in ad revenue over the life of her channel thus far," Fratella told CNBC Make It via email. Garcia has also secured partnerships with brands like Coca-Cola, Audible and Maltesers, and completed a 14-city meet and greet tour last summer. In May of 2017 she published a book, "Karina Garcia DIY Slime," and in October she launched a product line, Craft City, which includes a make-your-own slime kit sold exclusively at Target. She says that between ad revenue, partnerships, her book, product line, and events, her business earns about $2 million a year. One of Garcia's most popular videos to date has more than 23 million views. In it, she demonstrates how to make a stress ball out of 100 pounds of slime. Its popularity is a testament to the internet's growing fascination with slime. More than six million Instagram posts bear the #slime hashtag, and on Google's 2017 top trends list, "How to make slime" was the task most searched.

Michael Polk, CEO of Newell Brands, the parent company of Elmer's, told CNBC's Jim Cramer the trend has had a discernible impact on the company's business as well, as kids race to follow YouTubers' instructions. "Our brand managers identified the unbelievable trend with making slime, and one of the ingredients in slime, which is this ooey gooey creation, is Elmer's glue," said Polk. Retail sales of Elmer's liquid glue rose 25 percent in 2016, and Polk told Cramer that from March to May of 2017, the Elmer's brand had received nearly 200,000 social media mentions about slime.

Photo courtesy of Karina Garcia