My wife and I brewed up our first ever batch which initially went great. We hit our numbers, cooled the wort, transferred it to the fermenter and just as I was whisking a bit of O2 into the batch the whisk fell apart dumping a cups worth of sand, fibers, plastic, glass and metal into our wort.
Basically whatever they swept up off the floor in the Chinese whisk factory and tossed in the handle for weight went into the beer. After I used a magnet to pull metal chunks out of it we tossed the whole batch. It was just too gross to keep after that.