What’s a MacGuffin? Hitchcock said: Two Scotsmen are riding in a train. One asks the other what is contained in a package in the overhead luggage compartment.

“It’s a MacGuffin.”
“What’s a MacGuffin?”
“A device for hunting tigers in Scotland.”
“But there are no tigers in Scotland.”
“Well, then, it’s not a MacGuffin, is it?”

*fonte ** MacGuffin, McGuffin, Maguffin, tanto faz.