- "In the Shadow Lands beyond Asshai, they say there are fields of Ghost Grass, with stalks as pale as milk that glow in the night, murders all other grass. The Dothraki believe that one day, it'll cover everything, that's the way the world will end."
- ―Ser Jorah Mormont
On their travel east, Ser Jorah Mormont tells Daenerys that the Shadow Lands are said to be covered by "ghost grass", a form of grass that, in Dothraki mythology, will overrun the green grass of the Dothraki Sea and spell the end of the world.
In the books
The Shadow Lands lie beyond Asshai. To go to Asshai is sometimes described as to "pass beneath the shadow". It's unclear what "the Shadow" is.