The brothers get a tape player and once they hit play, the music causes them to dance uncontrollably. As they bring it back home, they see that anyone who hears the music starts dancing too.
When the brothers brought their new audio system back home, the instant they started playing it, they were suddenly seized by a strong and unexplainable desire to dance. As they continued on their way, they discovered that anyone within earshot was also affected, displaying a shared and inexplicable enthusiasm for movement.