Maladaptive Daydreaming is a medical condition in which a person will obsessively and uncontrollable daydream, this can be triggered from music, stories or nothing.
These Daydreams usually include: an idealised self, violence, rescue, capture, arousal, trauma, etc.
Most Maladaptive Daydreamer's have multiple worlds in there head, but all know that they aren't real.