For those of you who never played the gamecube games, Mirror B was unique in that he got his own special battle themes when you fought him. He's a dancer, and his whole team consists of lots of Ludicolo, fitting them theme.
Colosseum battle:
https://www.youtube.com/watch?v=Jp5ceMa5KXIXD GoD Battle:
https://www.youtube.com/watch?v=zlQhTuL608ESo let's have his copypaste use all kinds of bug pokemon, makes sense.
Like Reborn before it, this game loves to use the music of GlitchXCity, a youtube user who mainly remixes pokemon music. While I think most of her music is alright, it can't be stated how much she butchered Mirror B's XD theme, at least in my opinion
https://www.youtube.com/watch?v=TM9EImPSZTAThis is used in this fight, by the way. compare it to the above theme.