The Bad Place
"The Bad Place" is a world in an alternate universe which dreamwalker Kaia Nieves is inexplicably drawn to, calling it "the Bad Place." The dominant species of the word appears to be large kaiju-like creatures, though smaller humanoid figures appear to exist as well.
Kaia Nieves can see into other worlds by dreamwalking. One of these worlds, which she has dubbed "the Bad Place," was the only world she would visit in her dreams. It is a place of blood, death, and monsters. Any injuries she incurs in the Bad Place follow her into the waking world, causing Kaia to take amphetamines to stay awake.
Jack tracks Kaia down on the suggestion of Derek Swan, because he thinks she can help him rescue Mary Winchester from the Apocalypse World. Meanwhile, Patience Turner has visions that involve flashes of the Bad Place, where Sam, Dean, and Jody are being attacked.
With angels pursuing them to try and capture Jack, the Winchesters, Kaia, and Jack are cornered in an abandoned ship. In a last-ditch effort to escape, Kaia and Jack try to open a portal. Kaia takes a seat as Jack places his hands on her head and as the energy flows between them, Kaia is taken to the Bad Place, but with Jack's help she is able to pull away into the multiverse, where he is able to locate Apocalypse World. As the two mentally traverse the post-Apocalyptic landscape, they are able to reach Mary Winchester's prison. But Kaia's connection begins slipping, sending them back to the Bad Place, where a cloaked figure is stalking through the woods. Jack tells her to focus, bringing them back to Apocalypse World, until the strain becomes too much and Jack and Kaia send out a blast of energy that disintegrates the angels, sending Jack to Apocalypse World and Sam and Dean to the Bad Place. Regaining their composure after being transported, Sam and Dean begin exploring where they are, and unbeknownst to them find themselves standing in a gigantic footprint as a loud monstrous roar echoes through the land.