Why did it need two fucking mascot animals that both uses the joke of having a regular human guy name

Favorite movie as a little kid. Watched it tons of times. I haven’t seen it in years though, maybe over a decade. I remember being surprised that a lot of people only liked the opening sequence.
For some reason, I had this very vivid dream where Up was based on a book that I had. The book had a blue hardback cover, and it was big and wide like those Curious George collections. The book had black and white Shel Silverstein style illustrations. Russel died by falling off the zeppelin, and part of this dream involved watching the special features on the dvd and seeing Pixar interviews where they discussed why they changed it to have Carl adopt him instead. It was such a vivid dream that I still remember it, which is very rare for me, and I looked up whether Up was based on a book and it wasn’t.

>>143362994
Is that really a joke? I figured those were just names