Petergeist - S4-E26
Other mistake: The Griffins' house disappears when they flee, but when they go to Quagmire's house after, you can see their house when they are at the front door. Quagmire's house is on the right of theirs and the angle of the shot is to the left so it's definitely their house, not Quagmire's other neighbours on his right. (00:16:36)
Answer: Mort is Jewish, and Walt Disney was said to be antisemitic. So it would make sense in a Disney universe all the inhabitants would share his supposed beliefs.
MasterOfAll