With apologies to those who already understand...the punchline frame is a reference to "The Exorcist", wherein Linda Blair's possessed character is able to spin her head completely around. In relation to "looking the other way", it is indeed *unsettling*.
Took me a while to realize what kind of people can rotate their heads 180 degrees. But when the realization came, I laughed out...loud...And Dilbert's 2 words (That's unsettling) are too good.