The Cubs' Class A-Advanced team was on the receiving end of a questionable call, so the team's music man played "Three Blind Mice". The tune was not lost on the umpire who made the call, and he proceeded to eject the music player. With no music in the stadium, the Cubs allowed a fan to step in and introduce the players from the stands.
It's all so very minor league baseball. Never change, you weirdos.