The title of this episode is "Skulking Stranger."
It is overlaid over a red background.
The story of this cabinet is designed to teach children about reporting suspicious strangers.
Dimwit spends all of his time minding his own business; reporting a suspicious stranger is too much effort for him.
Duke, on the other hand, is always vigilant and always searching for those who don't belong.
This tale was likely conjured to encourage children to be on the lookout for the so-called False Prophet.