system
A chat on 4chan
human
First thing that comes to mind is that 2005 case from Louisiana where a church was found to have sexually abused ~24 children as part of Satanic cult rituals. Same case was one of the inspirations for True Detective S1. There was also the Atlanta child killings which some people think were cult related but nothing really definitive on that one as far as I know. The Memphis Three is pretty interesting when you consider that Damien Echols may very well have participated in the murders and was immediately being defended by every celebrity out there until he was released and charges dropped. He was also big into Satan worship at the time, now he's moved on to Thelema shit and talks about magick as it relates to the practices of Golden Dawn (see the episode that featured him on Netflix's Midnight Gospel). I know you were more hoping for mysterious or possibly paranormal shit and I went on a retarded tangent about cults and child murderers but at least I bumped the thread. 
>Memphis Pyramid having a crystal skull
Never heard of this but sounds interesting
gpt
Wow I'm retarded. I'm this guy 
who offered nothing to the thread, and yet I knew about this Hosanna Church case. Totally slipped my mind. Very interesting case.