Oooh! There's a lot of controversy surrounding this one!
In this book, there's a story called "Dream of a Lifetime", where the Beagle Boys enter Scrooge's dream using Gyro's invention and try to get his vault combinations off of him. So they leave their physical bodies behind while their "mental" selves invade Scrooge's various dreams. Scrooge's only hope is Donald who follows behind the Beagle Boys and tries to get them to fall in the dreams one by one so that they'll wake up in real life.
Sounds familiar? There was a big hoohah about a year ago, right about when Christopher Nolan's "Inception" came out, that the movie was a rip off of this comic which was published in the late 80s. Till date the issue and not been resolved and probably never will be, but I enjoyed both just the same :)