Could some material science person or engineer please elaborate what the wriggling black fibres on Covid masks are before it turns into the next conspiritard / pol mess? My guess would be residue from the manufacturing process or maybe a type of fibre that wan't colored properly.
You can get a sample of it by grabbing any random medical face mask, they are visible to the naked eye and start wriggling when you breathe on them. I've gone through a 12-pack of the regular blue-ish masks and found at least 2-3 fibres on each of them.