That was my inner voice screaming. My actual voice asking, What the *&^%* is going on? at least three times. It was a sudden, instantaneous event. One moment, I was trundling along in my Comanche 250 climbing slowly eastward over the Sierras, looking out at clear blue skies as the autopilot dutifully tracked the GPS toward my destination. Then, bam! The cabin filled with an acrid-smelling cloud. I could not see the instrument panel.