Although the Wastelands of Fallout are enough, there evidently appears to be other universes or dimensions parallel to the one of our world. And sometimes visitors from these other places pop over to cause some havoc.

More Fallout Videos:
The Aliens of Fallout
   • The Aliens of Fallout  

Will All Ghouls Turn Feral Eventually?
   • Will All Ghouls Turn Feral Eventually?  

Timestamps:
00:00 Introduction
00:31 Lorenzo Cabot
03:04 Psykers
04:14 Ghosts
08:23 UgQualtoth
12:30 The Interloper