Ghost (in ball pythons) is another name for Hypomelanistic. The term 'ghost' was applied early on when the first Hypos were produced however in other species the term 'Ghost' refers to a snake that is showing the traits of both Hypomelanism and Anerythrism (missing the red pigments) So many breeders now use the term 'Hypo' (short for Hypomelanistic) as being a 'more correct' term for the mutation.