This 1984 film had a working title of Teenage Mutant Comet Zombies, and is likely the most notable starring role for Star Trek: Voyager's Robert "Chakotay" Beltran. Catherine Mary Stewart plays a MAC-10 toting, Tempest playing valley girl in which film that saw most of humanity reduced to dust, and most of the rest reduced to flesh-eating zombies after passing through the tail of a dirty snowball?
Night of the Comet