From Bulbapedia, the community-driven Pokémon encyclopedia.
The Ditto Egg Group (Japanese: メタモン Metamon) is one of the fifteen Egg Groups. It is the only group which has only one member.
Ditto is the only Pokémon in the Ditto Egg Group, hence the group's name. Pokémon in this Egg Group have the unique ability to breed with any member of every other Egg Group, except for the Undiscovered and Ditto Egg Groups.
Only in this Egg Group
- As Pokémon in the Ditto group cannot breed with members of its own group, Ditto cannot be hatched from an Egg.
- Since this group consists of a single Pokémon, it is naturally the Egg Group with the lowest number of types represented, with just one.