What is up with this and is this a scam or fetish?

So earlier, I had some guy message me on messenger saying he was asking for volunteers and that he'd pay $20 for each. After asking what it entailed, he said he was taking biology and something else because he wanted to be a gastroenterologist. He then said he wanted women to take pics of their BMs, and what was wiped on t. p. (I'm not joking), and he wanted to write down the consistency, colour, etc and wanted to know what was eaten in the previous 24 hours. He said he was writing "a 13 page essay". I thought he was joking so I played along and he then said I could send as many "messy wipes" as I wanted. Of course after looking at his profile, I realized it was fake and blocked him. I've never had anyone ask me to do something like that before. Does anyone know what tf that's all about?

What is up with this and is this a scam or fetish?
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