Hmm... I try to avoid popular music with lyrics during a transformation, only because those types of songs have lyrics that can mess up what's actually going on.

Music like in the Hulk where it's a constant string or has some kind of rhythmic beat, or is a song dealing mainly with a transformation I think would best be suited for a scene like that.

But in all honesty?  I would prefer it with the music very, very subtle in the background almost hard to hear, because it's more about the sound effects of clothes ripping and women moaning, rather than the music.

And for the love of god no narration during a growth sequence!

Oh hell yeah, man! A symphony of ripping clothes, bulging muscles, and gutteral moans... although with Amy Lee, those moans might not be so gutteral  . Almost lyrical!

I agree on the no narration part. Let the growth speak for itself 

Also, what's so bad about a flute? I could see it underscoring the vulnerability of a woman hulking out. Confusion, ecstasy, I think the flute could help retain the wispier bits of the woman in the beginning, but by the end it had better progressed to some hard crunching heavy metal already or some such.

Oh.. let's see... Rammstein? >P
I LOVE them so much, and I always imagine one of my characters having such a massive growth spurt when listening to Mein Teil...
Industrial guitars are so awesome, heavy music just seems to totally warm up my mind to it.

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