Hej Monika was released in 2004 by Swedish band Nic and the Family and became a hit in Sweden that year. The song stayed mostly local until more than a decade later, when PewDiePie began using it in his videos and made it a running joke with his audience. Clips and remixes then spread across YouTube and meme pages, often linked in viewers' minds to Monika as a character name from games and anime. Its short, repetitive chorus made it easy to reuse, and it remains a nostalgic in-joke for fans of that era of YouTube.