Thanks and tweak ahead, it is public domain, as is all Greek mythology. Do you want the text?
Here is a Baku, a Japanese dream eater. They feast upon good dreams and as a result, nightmares form in those who they are feasting upon. They exist in another plane and very few people can see them, though they are more visible to magically aligned individuals and demons. This plane they live in is the border between dream and reality, and while feeding, the Baku often crosses the line into the realm of dreams. For the most part, they are not malicious and they feast and move on, so their victims do not suffer greatly.
There are those which haunt people, these ones are called Mares, and constant feeding leads to insomnia and night terrors in their victims. Mares can alter dreams to make them more horrific and therefore, they get more pleasure and sustenance from their victims. Eventually when their victims finally sleep, they are trapped in an eternal nightmare, leading either to death or a fate worse than death. To kill a Mare and other Baku, one must find them in their dream and kill them while dreaming, though this is very dangerous as Mares can strike back a la Freddie Kruger.
