Can't say I am shocked, on account of his age, but he was damn fine actor.
As I was too young to have watched him in Mission: Impossible (I discovered the series through re-runs of the 1980's version, which I still like), I remember him mostly for the part of sleazy (and hinted to be sexually ambiguous) henchman Leonard in North by Northwest, as well as equally sleazy Dr Alvin Kurtzweil on X-Files: the movie. But above all, it's his portrayal of washed-up Hollywood foreign horror star Bela Lugosi (which got him an Oscar, I think) in Tim Burton's Ed Wood that I am the most fond of. All his lines are priceless in that one, and delivered with such passion that it gave me more than once the impression I was watching the
actual Bela. Too bad there was no one to play Boris Karloff, but shhhhhh! Those who have seen the flick will get the joke