Suppose for a minute that there's a group of people traveling about your area, led by a charismatic speaker who claims that the world is ending soon. He promises he alone can save you, but only if you sell your belongings, devote the rest of your life to him, and cut off family members who try to stop you.
He may also want to change your name, advises you to leave your home/job if necessary to follow him, and says that if you don’t love him more than your own family, you’re not worthy of him. His followers have written a book about him in which he performs many miraculous feats, but no contemporaneous outside source corroborates their claims. What sort of group is that?