In Pokémon Red and Green there is unused text for extra badges, "Egg" and "Chick", "Bronze" "Silver" and "Gold", and what appears to be the names of unused Trainer classes. These strings are defined in the ROM directly after floor names, which follow on from item names, meaning that the unused text can be forced as glitch items. The text remains untranslated in the localised Red and Blue, and Egg and Chick are kept with the names "たまご" and "ひよこ" respectively. This results in illegible text in the English versions, because the character table for the localised Generation I games is incompatible with Red and Green. It is unknown what "Egg" and "Chick" would have referred to, or whether the concept was a precursor to Pokémon eggs. The text matches early Capsule Monsters artwork in which an unknown creature can be seen fleeing from an egg. The concept may also be reminiscent of the Fresh egg and Chick items in EarthBound, in which the player would keep the Egg until it hatched into a Chick, and then raise the Chicken and eventually sell it. EarthBound was a game that Ape Inc. developed; the company that eventually became Creatures, Inc.
In the anime, Shellder is required to evolve Slowpoke into Slowbro or Slowking. Shellder clamps onto a Slowpoke's tail to evolve into Slowbro, or onto its head while wearing the King's Rock to evolve into a Slowking. Even though Shellder changes form drastically when it bonds with Slowpoke to evolve, it is not considered an evolution in and of itself.
Kangaskhan carries around a little purple baby Kangaskhan in their pouch. The baby Kangaskhan lacks the ridges and patches on its mother’s body, and its small fangs are not visible outside of its mouth. Even with the advent of breeding and baby Pokémon, the baby Kangaskhan has yet to be made into a separate Pokémon, and as a result, all Kangaskhan are born with a baby already in its pouch. As part of Kangaskhan's Mega Evolution, however, the baby is capable of fighting alongside its mother.
According to interviews with Ken Sugimori in Nintendo Dream, the bones that Vullaby and Mandibuzz wear are those of other Pokemon. However, it is not stated which Pokémon they are from, and as the skeletal systems for the majority of Pokémon have yet to be revealed, it is unknown if they are meant to be the bones of a specific Pokémon. However, the skull that Vullaby wears as a nappy is similar to a human skull, which may inicate that the bones are from a Pokémon in the Human-Like Egg Group.
The origins of Zekrom and Reshiram are told in legends, as they were once a single powerful Dragon Pokémon used by twin heroes in order to create the Unova region. But the brothers each sought something different in life—truth for the older brother and ideals for the younger—and they began to argue, then fight, over who's side was right. The single dragon, in response, split into two Pokémon: Reshiram, who sided with the older twin, and Zekrom, who sided with the younger twin.
It is possible that Kyurem is what is left of the original dragon Pokémon.
While Genesect is a cyborg Pokémon, it did not previously take this form. The modern Genesect was revived by Team Plasma from a fossil of this Pokémon, and modified into its present appearance. According to Genesect's Pokédex entries, it existed over 300 million years ago, and was feared as a powerful hunter. Due to its lack of Team Plasma alterations, it is unlikely that it would have been part Steel-type, nor would it have access to Techno Blast or similar moves.
A silhouette possibly of a Pokémon was discovered while rummaging through coding of the recently launched Trading Card Game Online. This silhouette was discovered in the navigation bar on the game's tutorial page, combined with images of the Unova starter Pokémon. No additional information on the silhouette was contained in the source code of the tutorial's Flash file. According to Serena Robar, a community manager for The Pokémon Company International, it is not a new Pokémon, but is actually just a placeholder image that wasn't removed after the code was decompiled.
In The Ghost of Maiden's Peak, a Gastly, who had the ability to create illusions that were solid enough to attack people, created a crossbreed of a Blastoise and a Venusaur, calling it a "Venustoise".
The only known information about this creature is from its brief appearance in EP072. It seems to be a bear, and thus bears similarity to Honōguma, Teddiursa, Ursaring and Cubchoo. It has decorative markings covering its body; due to the fact that markings like this are also present on the other Pokémopolis Pokémon feautured in the episode, such as Gengar and Psyduck, it is unlikely to have been a normal feature. It is unknown whether it was intended to be in the games, however with its rounded ears, brown colour and cub-like appearance it seems to be very similar to Teddiursa.
This creature made its sole appearance in EP138. It seems to be a giant yellow spider, with four red compoundeyes, two antennae on its head, and a mouth with four large fangs. It has a thorax with eight long brown legs. Its abdomen is much larger relative to the rest of it body, with two thin black stripes. Its cry has the sound of a scream, not unlike Victreebel's. The nature of it appearance (in a Gligarman movie) would appear to indicate it may be a fictional monster or Pokémon, and whether it is supposed to be portrayed by a real Pokémon, a mecha, or simply special effects is unclear, though its movements and its cry give it an extremely organic appearance. Due to its appearance rather early into the Johto series of the anime, it is unlikely to have been intended to be in the games, and can be considered to be an anime-exclusive Pokémon.
The only representation, albeit in statue form, of the aquatic life that Kabutops is said to have feasted on in most Pokédex entries since Red and Blue.
It bears similarity to the Clay Doll Pokémon Baltoy and Claydol. Due to this, it may have been based on shakōkidogū - a "spaceman" clay figurine from the Jōmon period of Japanese history.
Unreleased Unown. Due to the introduction of two additional Unown forms in Generation III, some fans have speculated that these may have been very early prototypes for new forms of Unown. Some of the letters resemble Я, Ω, Σ, б, Д, ω, Π, and σ.
An evil monster that attacked the city of Alto Mare was seen in the Japanese version of Pokémon Heroes. The storybook style segment of the movie, which told the story of the origin of the Soul Dew and Alto Mare's ancient history, was completely cut from the dub.
This unknown Bug-type Pokémon was captured by Isamu Akai in The Big Battle In The Viridian Forest!!. It was his second Pokémon, after Clefairy. Other than the fact that it is a Bug-type, the only other thing known about this Pokémon is that it's supposedly very weak. It escaped from its Poké Ball in the same chapter.
In the Pokémon Adventuresmanga the statue in Eterna City is neither Dialga or Palkia but a combination of the two statues. This is a reflection of the statue's appearance in Pokémon Diamond and Pearl and Pokémon Platinum being ambiguously shaped in order to represent a different member of the duo in each game.
MechaMew2 is a Robotic Pokémon seen only in Pokémon Live!. It is considered by its creator Giovanni to be the most powerful Pokémon in existence. Giovanni promised Trainers the very rare Diamond Badge to anyone who could defeat it. MechaMew2 is based on Mewtwo, another Pokémon whose creation was ordered by Giovanni. It destroys itself at the end of the show after learning an attack of love, caring, and friendship.