From Modern Mechanix blog, here is a portable darkroom "hoodie":
When regular darkroom facilities are not available, photographers may have a practical substitute in a portable one in the form of a close-fitting piece of rubber material that slips over the head like a hood. It contains a square of ruby glass for developing and changing plates, etc. At the bottom, it fits tightly to the body so that no light is admitted, but its folds are loose enough to permit ample freedom for the arms and hands. It can be quickly wrapped into a compact package and fits in a small space in the camera case.