In an attempt to be more environmentally friendly, Adidas is introducing a running shoe made from biodegradable artificial spider silk that will melt away when you’re done with them. Once you’ve worn out your pair (the company recommends two years of use), you can immerse the shoes in water, add a digestion enzyme called proteinase, and let it work for 36 hours. It will cause the protein-based yarn to break down, and you’ll be able to send the liquefied shoes down the sink-all but the foam sole, which you’ll still have to throw away. Adidas says the shoes are 15 percent lighter than comparable running shoes, while remaining strong and durable. They are non-allergenic and vegan. And, if you’re wondering, they will not melt on your feet in the rain because the proteinase enzyme is required for biodegradation.