WARNING: If you don't want to know what happens in this episode, don't read this photo recap!
So, last we saw Margo's dad, he was eating a corpse of Margo's mom. And now, it turns out that Margo can't remember her mother. It's because her dad ATE HER MEMORIES of her mother. That's what that was. He tells her that he thinks she's seeing him because she needs him. That's why all of this is happening.