We can always use more case studies of insanity that aren't religion, right?
Well, Miracle Mineral Supplement is my new go-to example for Bad Things happening to people with low epistemic standards. "MMS" is a supposed cure for everything ranging from the common cold to HIV to cancer. I just saw it recommended in another Facebook thread to someone who was worried about malaria symptoms.
It's industrial-strength bleach. Literally just bleach. Usually drunk, sometimes injected, and yes, it often kills you. It is every bit as bad as it sounds if not worse.
This is beyond Poe's Law. Medieval blood draining via leeches was far more of an excusable error than this, they had far less evidence it was a bad idea. I think if I was trying to guess what was the dumbest alternative medicine on the planet, I still would not have guessed this low. My brain is still not pessimistic enough about human stupidity.
I am constructing an artificial language (just for fun; also it isn't going to be finished any soon) with three grammatical numbers: singular, plural (can be any number, zero and one included) and class plural for everything in the class. I have invented this independently of Tolkien not for practical reasons, but just for sake of elegance, as it better suits my desire to have the grammar work in part like set algebra.
Having grammar rules that enforce expressing the number more precisely than we are used to (e.g. different grammatical numbers for one vs. two vs. more than two but few vs. noticeable minority vs. majority vs. all) has disadvantages when the speaker doesn't know the number or just wishes to describe a general situation where more than one number is applicable. Similar problems we face when our grammars enforce gender expression when using some pronouns (if we aren't Finns or Turks or Chinese or...). People try to find a way around, either by using more complex expressions ("he or she") or by attempts to update the grammar / vocabulary ("ey"). I am not sure whether I'd wish to have the same problem with grammatical number.
As for Welsh, a peculiarity with plurals I know about is that some nouns, usually denoting animals, have the basic (shorter) form denoting plural and the singular is derived by a suffix (e.g. adar/aderyn for birds/bird, pysgod/pysgodyn for fish, plant/plentyn for children/child - children are apparently sort of animals too). I haven't heard/read about different types of plural though.