Want to give the next-season mystical trend a go, but can't imagine how it will look anything but Halloween? Well, inspiration is at hand, as major magic vibes are one of the most exciting new looks for SS16 — and all-black everything is a surprisingly fresh alternative to pretty pastels. See Rodarte rocking it on the runway, Miroslava Duma putting the dress-game under her spell, and how you can join the coven…