Return of the K-Riddler
If you spell my color
And switch the first letter
With the next one alphabetically down
Makes a transformation
As my color then becomes my sound
What am I?
HINT1 When I say “the next one alphabetically down” by “down” I mean “closer to A as opposed to closer to Z.”
HINT2 The color is not universally accurate, but the classic depiction of this thing almost always show it as being this color.
HINT3 Yes, I am proposing that “color” sort of rhymes with “letter.” Hey, it’s a riddle, not a sonnet!
Comment of e-mail if you need to know the answer.