I'll also go 67 with Two By Twos. They're a purposely obscure/behind-the-scenes cult where members of the church (which officially doesn't even have a name, most outsiders just call them that) live among those who wish to convert, and there have been massive per capita sex abuse scandals with them lately, because it's these initiated "priests" living with random people for a long duration of time to make sure they're "real Christians". They're a pretty outlandish one and I've never seen anyone discuss them here

https://en.wikipedia.org/wiki/Two_by_Twos