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 VII, 103 Pokémon belong to this group.
The Undiscovered Egg Group is characterized by its members' inability to breed. Most of the Pokémon in the group are either baby Pokémon, Legendary Pokémon, Mythical Pokémon or Ultra Beasts.
Baby Pokémon are designated for this group due to them being too immature to breed, while Legendary Pokémon, Mythical Pokémon and Ultra Beasts are included to prevent players from breeding and obtaining more of them in a given game (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. Cosplay Pikachu and Ash-Greninja are included here even though others of their species are capable of breeding.
In Pokémon X and Y, 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 or obtained as a gift (except via Mystery Gift). In Pokémon Omega Ruby and Alpha Sapphire, this only applies to Legendary and Mythical Pokémon.
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 Mythical Pokémon not in this Egg Group are Phione (whose Mythical status is disputed) and Manaphy, which are in the Water 1 and Fairy groups.
- Despite not being in this Egg Group, Manaphy is still guaranteed three perfect IVs when obtained from an event.
- This is the only Egg Group that contains a Pokémon of every type.
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