B2ST/Beast is one of the few groups that make music videos because fans like the song (Super Junior does this too. Yay!). Their 'special' for-the-fan music videos are intriguing and often surprising. In Mystery, some guy finger skateboards everywhere - through music video props, onto official Tech Deck ramps, and through chess sets. Meanwhile, the Beast members sing passionately. Then... break out the break dancing, finger break dancing! (Tiny shoes, meet tiny dancing fingers.) The music video, with lots of black costuming and lighting, and the finger skateboarding/break dancing, is more masculine than I expect Kpop videos but in an unexpected way. It's almost like they're gently trying to increase their male fanbase, while providing their fans interesting visuals.
The song, Mystery, is catchy and fun. As expected from Beast, their for-the-fan music video songs are a cut above the rest.