I was in a FAST double pace line of perhaps 50 riders on an organized ride in Illinois a few years back when a horse started pacing us in a field to our left. Unfortunately, the field was not fenced, the horse stumbled, veered left, and ran right through the pack. Talk about "shattering" a peloton. Fortunately, no one went down, but for the rest of the ride, we never saw the 20 that got cut off.