Transcript:
Sylvester Shyster has an interested Minnie alone and tells her "My dear Minnie.―Now that we are alone, I must tell you that the old Mortimer estate you've inherited is practically worthless!!―But because you are my friend―and I have a heart of gold―I'm going to take it off your hands for a small sum!!"
Mickey observes through the keyhole and says to himself, "Gosh! He's trying to buy the estate from her―Now I know why he put me out of the office―Yeh―He's got a heart of gold―Yellow and hard!!!" A shadowy figure appears behind Mickey with a piece of paper and pin
Mickey shouts "WOW!" in pain as the note is pinned to his rear and the shadowy figure disappears
Mickey holds the note toward the reader, which says "Warning!―Don't let Minnie sell the Estate!! The Fox!" Mickey also looks towards the reader and asks "Who-o-o-o-o who is The Fox??
I'd like to think that the Mortimer Mouse from Bloom County is the Mortimer in question: