For all those who still think the Yanny/Laurel thing is witchcraft...
Go to your Windows (sorry Apple folks, figure it out on your own. Ask the ghost of Steve Jobs) audio settings. Find your output device. Go to Properties. Go to Enhancements. Go to Pitch Shift (not available? You are hopelessly stuck in Yanny/Laurel land. RIP). Change Pitch to +4, listen to clip (Laurel. High pitched frequency shift. People sensitive to high pitches, hear this). Change Pitch to -4, listen to clip (Yanny. Low pitched frequency shift. People sensitive to low pitches hear this).
That was the second thing I did, after messing with my equalizer to hear any BS that might mean it's layered (like the clear L sound at the beginning of "Yanny" in certain EQ settings).
Also, the dress was Blue and Black with gold stitched in to make it shine and contrast in bright lighting. Camera flashes and bad photoshopping do the rest.
/fun
RIP.