The latest in the rush of nostalgic trends, butterfly-core covers make-up and hair. If I were a statistician, I would describe the return to nostalgic tropes as a “hockey stick” curve.

The American singer, 27, whose real name is Kayleigh Rose Amstutz, underwent a transformation for the event, swapping her usual makeup look for symmetrical, butterfly-inspired face paint.

Known for its shimmering blue wings, the Morpho butterfly owes its brilliance not to pigments but to microscopic structures that manipulate light. Now, researchers are harnessing those same structures ...