Yellow

An email I just received about a conversation between my nieces and sister in-law:

My conversation with the girls today...

Ashley: When are we going to see Kimmy again? I want to go to Wyoming.

Sariah: Kimmy lives in the yellow stuff.

Me: What? What is the yellow stuff?

S: You'll just see when you get there.

M: Ok, but what are you talking about?

S: It's just the yellow stuff. And she has a fountain that has really stinky water. And there are lots of trees and mountains. And Kimmy lives outside. She doesn't have a house.

M: Kimmy does not live outside. Do you mean Yellowstone?

S: Yeah. Yellowstone.

(She continued to refer to it as yellow stuff for the rest of the car ride.)