If you're a boy band-loving kid of the '90s, you would be able to recognize the voices of the Russian Dolls in a heartbeat. The perfectly matched harmonies point to the Hanson brothers, most known for their 1997 single "MMMBop." Not only do the Russian Dolls sound like Hanson, but some of the clues point to the brothers as well.
For instance, in the first video, you could see 15 Russian doll replicas in the background. Combined the Hanson brothers — Isaac, Taylor, and Zac — have 15 children (via Screen Rant). They also mention in the video that they were once the hottest toy on the shelves, but were "cast to the side" for newer ones (via YouTube). That could be referencing how they've been making music since the late '90s, but haven't quite matched the success of their first single. It was also snowy in their clue package, which could reference their Christmas album, Snowed In, and the milk on the shelf could be a nod to their Got Milk ad in the 1990s. In their second appearance, there's even a reference to one of them being rushed to the hospital, and in 2007, Isaac had to undergo surgery for a pulmonary embolism (via Tulsa World).
Whether or not it is Hanson, the fan theories are strong with this one. And if you're a Hanson fan, you may just want to tune into The Masked Singer to find out.
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