A few nights ago, a couple of my friends (who aren't christians and are very into meditation, spiritual experiences, etc.) made a ouija board and experimented with it. They said they met a group of "people" and were talking with them for hours. They've been documenting their conversations and everything. My friends told me their names and their stories and that they've been doing this for 3 or 4 nights in a row.

I know they're communicating with demons, and im not sure what to do. They actually believe they're talking to dead people in a sort of limbo. If i try and tell them they're actually talking to demons posing as dead people, they won't believe me, and will roll their eyes, basically.