Which comet did Mark Twain famously say he came in with and would go out with?

Mark Twain famously said he came in with Halley’s Comet and expected to go out with it.

Samuel Langhorne Clemens, known as Mark Twain, was born on November 30, 1835, shortly after Halley’s Comet reached perihelion. The comet returns to the inner Solar System roughly every 75–79 years, making it a fitting subject for Twain’s darkly playful prediction.

In his autobiography, Twain wrote that he expected to die when the comet returned, adding that the two “unaccountable freaks” had come into the world together and should leave together. Halley’s Comet returned in 1910, and Twain died on April 21 of that year, one day after the comet’s perihelion passage.

The quotation is often treated as a precise prophecy, but Twain made it as a witty literary remark rather than a scientific prediction. The comet’s 1910 appearance also overlapped with public anxiety about comets and rumors that their gases might be dangerous.