Idea of what Mystery Rituals were like

Happened to be watching a YouTube video about something completely different & there was a section where the youtuber quoted pretty much an entire tablet describing a closed religious ritual from the middle east. Sounds extremely similar to how the little bit we do know about mystery rituals in Greco-Roman culture were supposed to work- they are acting out a myth. It's a complete description of what everyone is supposed to do & say & why & then ends with laying a curse on anyone who either destroys the tablet or reads it without permission, meaning it was a closed ceremony, too. I figured Hellenists would find it interesting.

Anyway, its about a 5 minute long read & shows up roughly at the 30 minute mark of the video:

https://m.youtube.com/watch?v=Lex62EK2wJE