(to) turn into a Scotsman

In episode 7, "You're No Fun Anymore" (first season, airdate 11/30/69) of Monty Python's Flying Circus, a number of characters turn into Scotsmen and vanish from the narrative. (Well, actually, they don't vanish so much as they immediately depart for Scotland. Which amounts to the same thing.) TheLarch and I will sometimes make this reference before going AFK or signing off from the channel.