One of his best lines to Columbo was "I don't care what visions you see when you look in your cigar ashes." (Comparing it to tea leaf reading and things like that.) He repeated the line later, when Columbo told him one of his deductions, sice he couldn't seem to prove it - "More cigar ashes." So it really started to sound like an actual expression.

My favorite Conrad line in that ep is "When I grow, Gene, you grow." It's the slogan for his whole scam.

Robert Conrad trivia for "Columbo" fans: He was born Conrad Falk (or, depending on the source, Konrad Falkowski).