Speaking to Cosmopolitan, Karina revealed that she got started in the slime business after finding that there was a lack of recipes online for making slime, which she used to play with as a kid.
"I got obsessed with slime, out of nowhere," she said. "There was only like, one recipe for a basic Gak [a slimy modelling compound] online. So I just decided to go with it."
After her sister, who has her own YouTube channel doing beauty tutorials, encouraged Karina to create her own account, she was off and running.
The slimes created on Karina's channel come in all colours, packed with glitter, and are even sometimes edible - such as the pink Starburst video from last year that has more than five million views.
In seven months, Karina began making money from her slime videos. Very soon after that she was supporting her whole family, including her parents and her siblings, through her hobby.
The money comes not from the recipes or slime sent out to customers, New York Times reports, but rather from sponsorship deals and other advertisers including Coca-Cola and Disney.
The sponsorships can come with cheques of between US$30,000 and $60,000, with Karina revealing that she makes more than $100,000 total every month.
"There are times when it's $200,000 in a really good month," she said. "I've retired my parents. It's definitely really crazy. Even I can't believe it."
