Core 77 reports: [edited]
The now-on-Kickstarter Musguard is a blade-like strip of polypropylene that is affixed to one's seat tube with a velcro strap, fixed in place at the seatstay bridge such that it sits almost directly above the rear wheel.
The Musguard is produced locally in Slovenia, and is not only removable and rollable but also recyclable as well:
Musguard is looking to reinvest some of their Kickstarter funding in developing a matching front fender. They surpassed the $10,000 funding goal within just a few days of launching their campaign about two weeks ago.