Here are some of the sources that inspired Mythicals:

• What Is the Multiverse? Parallel Universes Could Be Hospitable to Life, Scientists Say
• Aliens May Well Exist in a Parallel Universe, New Studies Find
• Our Universe Could Be an Expanding Bubble in an Extra Dimension
• This will blow your mind! Universe sits on BUBBLE of energy in sea of alternate dimensions
• Alien Base and Flying Saucer Found in Antarctica
• Google earth reveals strange Antarctic entrances – evidence of secret UFO bases?
• Navy Engineer: I Saw UFOs, Aliens, And Top-Secret Bases In Antarctica
• Glowing Auras and ‘Black Money’: The Pentagon’s Mysterious U.F.O. Program
• Fantastically Wrong: The Strange Real-Life Origins of the Fiendish Werewolf
• Are Werewolves Real and Existing?
• Pixies
• Could a multiverse be hospitable to life?
• Have scientists found evidence of a parallel universe?
• Is Our Universe One of Many? Here’s How We Can Find Out
• The Catastrophic Effect of an EMP Attack or Severe Solar Storm
• The Catastrophic Impact of a Chinese EMP Attack Upon America
• Experts: Civilians not ready for EMP-caused blackout
• Report of the Commission to Assess the Threat to united States from Electromagnetic Pulse (EMP) Attack

See also the Sources that inspired Wormholes