96p/machholz is unusual among comets in several respects. its highly eccentric 5.29 year orbit has the smallest perihelion distance known among numbered/regular short-period comets, bringing it considerably closer to the sun than the orbit of mercury. it is also the only known short-period comet with both high orbital inclination and high eccentricity. in 2007, 96p/machholz was found to be both carbon-depleted and cyanogen-depleted, a chemical composition nearly unique among comets with known compositions. the chemical composition implies a different and possible extrasolar origin.