Battling or talking to either vocalist before the fight against Roxie will remove their sound from the background gym theme
>>28572480
S.S. Anne
>>28572480
Also in the Japanese release Roxie sings the words D O G A R S.
This is both koffing's Japanese name and part of Black/white's soundfont.
>>28572480
In the same arena there is a poster near the entrance where a singer is looking for a band.
https://www.youtube.com/watch?v=Acm2xl417wk