When an expatriot showbusiness personality goes insane due to an inablility to cope with the strong and unique American culture they are thrust into via fame. Precursors are, freakishly odd quotes in interviews and outlandish behaviour in public.
Examples are William Shatner, Bono, Corey Haim, Mel Gibson, Margo Kidder, and Howie Mandel.
Terrance "No, I hate shows about washed up celebrities. Why?"
Coco "Because Corey Haim totally Shatnered"
Example: When the 2010 Winter Olympics closing ceremony went from the moving extinguishing of the Olympic flame to the tune of Neil Young's "Long May You Run" to William Shatner discussing the hazards of having sex in a canoe.
Leonard told Scotty his breath smelled like a rotten hemmoroid. He really "Shatnered him!