The World Series begins Tuesday night between the Washington Nationals and the Houston Astros, and this year's previews include a strange explainer: why the song "Baby Shark" is such a hit with Nationals fans. It began in low-key fashion in June when Nats player Gerardo Parra adopted the kids' ditty as his walkup song before at-bats.
At the time, both Parra and team were slumping. He got a hit the first time the song played, the team started winning, and the song stayed. Now, it's a thing. Fans not only sing along, they do the hand motions. In fact, the players have adopted the hand motions after base hits: small "baby shark" finger pincers for a single, bigger "daddy shark" hand motions for a triple, etc. So why did Parra choose the song? His 2-year-old daughter, Aaliyah Victoria, loves it.
Source: HERE