YouTuber NileRed mixed up a batch of DNBP, a photochromic compound that changes color in sunlight. Then he moulded it into a bear and put it out in the sun, with fascinating results.
For those who skipped that day of chemistry, DNBP is 2-(2′,4′-dinitrobenzyl) pyridine. He tried to make a photos with it, but the bear turned out way better.
• Experimenting with Photochromism (YouTube / NileRed)