Fleischer's Comet is a comet and it is featured in the second part of the episode "Little Girl Lost" of Superman:The Animated Series.
Named after the person who discovered it on Earth, Fleischer's Comet was scheduled to pass Earth sometime in the late 1990's. Like most comets, it is bigger than a meteroid and differs from an asteroid only by its coma or tail and where they are formed. The tail is due to solar radiation that occurs near the nucleus when the comet enters the inner solar system and vents volatile materials. The nucleus is a combination of dust, frozen gases, such as ammonia, carbon dioxide, and methane, and rocks. The nucleus has a low mass because of its composition and thus, is not a perfect sphere. Comets are formed in the outer solar system while the asteroid, in the inner solar system. They range in size from 100 meters to over 40 kilometers. The elliptical orbit of comets can range from 200 to a million years but often disintegrate due to exposure to The Sun's gravitational field or collision with other objects. Astronomer Doctor Cornell guaranteed the press that Fleischer's Comet would not come anywhere near Earth.
However, Fleischer's Comet was a boon to Darkseid as he wanted to find a way to alter the comet's course. Unable to invade Earth without provoking the Highfather and the New Gods of New Genesis, thus violating the pact between New Genesis and Apokolips, he decided to alter the comet's path to impact on Earth and trigger utter devastation. But he would have to do it without an Apokoliptian weapon. Granny Goodness along with the aid of the Female Furies and the Intergang, was dispatched to Earth ahead of time to build such a device with Earth technology. Soon enough, the Doomsday Magnet was completed. In the aftermath of the disaster, he could send "emergency aid" without violating the pact with New Genesis.
During an unforeseen battle with Supergirl, the Magnet was activated. Due to her inexperience, Supergirl impulsively smashed the Magnet which didn't reverse the effects of the comet's path to Earth. Superman and Supergirl flew into near space to deflect it with their strength alone. However, as Superman appeared to have succeeded, the comet broke off. Supergirl tried to redeem herself and was badly injured. Nonetheless, the comet was returned to space and most likely disintegrated in time.
- This comet's name is derived from Fleischer Studios, which produced 9 out of the 17 "Superman" serials released during the 1940's.