After The Aurora Crisis a powerfull pokemon known as 5l33p or Sleep is said to have Nightmare Power Similar to Darkrai However This is not like it. has it is a Myth of the Sinnoh Region The Myth States. "This Pokemon Caused a Disaster so Called "Nightmares Come to Life Crisis" 50000 Years Ago so its believed for this to happen every 50000 Years " In This Crisis It Says that Nightmare of Soul Comes True to Existance but the common believe is that all living things falls to slumber but nobody Knows what happened that caused a Fossil of an unknown pokemon believed to be a nightmare no concludes yet or Accepted Theory But TO BE CONTINUED.
Special Monsters of Chaos: Chapter 18 : Nightmarish Crisis
by Raijin Zen