Maybe I'm to Old to Understand

I talked to my niece on the phone this morning. Four years old. She had just woken up and wanted to tell me about the best dream ever.

Kyra: Aunt Steffie, I had the most good dream ever.
Me: Oh, I wanna know what it was about.
Kyra: I found a monkey at the park and it was dead. And Megan found another one and it wasn't dead yet.
Me: Oh, wow, cool.

*boggle*
Where do kids get this stuff, and what could it possibly mean?
(sidenote: she doesn't know anyone named Megan, per what her mother said)