When one thinks about Kelsey Grammer one thinks about Frasier Crane, the character he so skillfully portrayed for 20 years on 'Cheers' and then 'Frasier.'

But the 57-year old actor is also responsible for 'The Simpsons' favorite bad guy Sideshow Bob, another pretty noteworthy and long-running television fixture.

Grammer first met Conan O'Brien when O'Brien used to write for 'The Simpsons.' So it seemed appropriate for the pair to discuss Sideshow Bob during Grammer's appearance on 'Conan' Monday night.

Among the details we learned about the homicidal super villain is that his propensity to break out into song comes from Grammer's own life. Apparently Grammer had a habit of singing standards during the shooting of 'Cheers' and Sam Simon, who wrote and produced 'Cheers' before developing 'The Simpsons,' recommended Grammer incorporate this trait into Sideshow Bob.

Among other Sideshow Bob tidbits revealed is that his dramatic, mid-Atlantic-like accent comes from the late stage actor Ellis Rabb, whom Grammer was friends with. Grammer also told Conan his favorite Sideshow Bob line: "Well Lisa, you don’t spend ten years as a homicidal maniac without learning a thing or two about dynamite," he recited, letting the "thing or two" dangle for a moment just like Sideshow Bob would.

What's your favorite Sideshow Bob line or moment?