Amorphous

Bodies with no fixed shape: gases like Gastly and Koffing, sludge like Grimer and Gulpin, candles like Litwick and sea slugs like Shellos. Over half are ghosts: 36 of its 63 species are Ghost type.

The Amorphous egg group has 63 species, 40 of which belong to this group alone. The group it shares the most species with is Mineral, with 7. Between them they can breed with 447 different species, Ditto included. All of them can breed with Ditto, and for the 5 genderless ones it is the only possible partner. Of these, one is always male and 2 always female, and two of the same gender cannot breed with each other even if they share a group.