From Bulbapedia, the community-driven Pokémon encyclopedia.
The Undiscovered Egg Group (Japanese: タマゴみはっけん Eggs Never Discovered), known in Pokémon Stadium 2 as the No Eggs Egg Group, and the No Eggs Discovered Group in Pokémon X & Pokémon Y: The Official Kalos Region Pokédex & Postgame Adventure Guide, is one of the fifteen Egg Groups. As of Generation VI, 81 Pokémon belong to this group.
The Undiscovered Egg Group is characterized by its members' inability to breed. Other than Nidorina, Nidoqueen, and Unown, all of the Pokémon in the group are either baby Pokémon or Legendary Pokémon.
Baby Pokémon are designated for this group due to them being too immature to breed, while Legendary Pokémon are included to prevent players from breeding them (with the exception of Manaphy). The reason why Nidorina and Nidoqueen are in this group has been widely speculated since their inclusion in it in Generation II.
In Generation VI, all Pokémon in this group are guaranteed to have a perfect 31 in at least three of their individual values when caught in the wild.
Only in this Egg Group
- This and the Ditto Group are the only ones in which all members are in a single group, since being a member of any other Egg Group would defeat the purpose of being in the Undiscovered group.
- Nidorina and Nidoqueen are both in this group and therefore cannot breed; however, their respective male counterparts Nidorino and Nidoking, as well as their pre-evolution Nidoran♀ and its male counterpart Nidoran♂, are able to do so.
- The only Legendary Pokémon not in this Egg Group are Phione and Manaphy, which are in the Water 1 and Fairy groups.
- This is the only Egg Group that contains a Pokémon of every type.