Franchise: Pokémon

Haunter's cry changed from generation to generation. In Generation I, it had a humming noise accompanied by a beeping noise. In Generation II, the beep's pitch changed to a jingle similar to a Magneton's cry. In Generation III and onwards, the beeping was removed entirely, leaving behind only the humming.

Two early Pokemon designs are named 'Godzillante' and 'Gorillaimo'.
'Godzillante' is most likely based on reptilian monster Godzilla, and
'Gorillaimo' could be based on Donkey Kong or the Universal monster King Kong. Not much is known about either Pokemon. Their designs could have been developed into other Pokemon, as they vaguely resemble Tyranitar and Slaking.

Throughout the Pokémon series are several references to a previous Game Freak game, Pulseman. Two of the most well known references are Barry's battle theme having very similar notes to Pulseman's first stage, and Pikachu's move, Volt Tackle, also being an attack from Pulseman. In Super Smash Bros. Brawl onwards, Pikachu's Volt Tackle Final Smash shares a similar appearance to Pulseman's Volt Tackle.

With the exceptions of Sada and Turo in Pokemon Scarlet & Violet, all main series professors are named after a type of tree.

The default character 'Red' had a short cameo appearance in the Pokemon Anime as a character in a movie.

In every generation there is at least 1 small legendary Pokemon with a base stat total of 600 and a stat distribution of 100 all around.

Deino, Zweilous, and Hydreigon reference numbers in the German language. Ein(s) is one, zwei is two, drei is three.

In the english versions of Pokemon, there are the Pokemon "Hitmonlee" and "Hitmonchan". The English names are references to Bruce Lee and Jackie Chan.

In the Japanese version it's "サワムラー" (Sawamular) and "エビワラー" (Ebiwalar). Sawamular is a reference to Tadashi Sawamura, the one of the first kickboxers. Ebiwalar is derived from Hiroyuki Ebihara, a Japanese world-champion boxer.

The non-damaging and non-effect move Splash is a mistranslation. It's move name in Japan is はねる (haneru) which can be translated as both Splash and Hop (although usually as the latter). This mistranslation was mostly a result from the exclusive usage by Magikarp in Generation I.

This also explains why this move can be learned by non-aquatic Pokémon such as Hopip, Spoink, and Buneary for their nature of hopping and why it is disabled by the move Gravity.

Pikachu has had four balloons in the Macy's Thanksgiving Day Parade. The first one (nicknamed "Flying Pikachu") ran from 2001 to 2005. The second one was a redesign that now featured him chasing a Poké Ball balloon and ran from 2006 to 2013. The third was another redesign featuring him wearing a green scarf and holding a small, Pikachu-shaped snowman, ran from 2014 to 2020. In 2021, the fourth balloon was introduced, featuring Pikachu and Eevee riding in a bobsled resembling a Poké Ball.

Pikachu is the second video game character to be featured in the parade after Sonic The Hedgehog in 1993.

The first 4 regions are based on real life Japan.

In some of it's Pokédex entries (namely Yellow and Gold), Slowbro is said to turn back into Slowpoke if the Shellder on its tail comes off. This and most of Exeggutor's entries (which states that if its' heads fall off, they will become an Exeggcute) are the only Pokémon that mention devolution.

According to studies carried out by Iowa State University, the Pokéwalker is one of the most accurate pedometers ever.

Until Generation III, the Normal type is the only type to have multiple type-enhancing items.

The Swirls on Poliwag's stomach are actually based on real life tadpole's intestines.

The Pokemon 'Drowzee' is based on tapirs, which, in Japan, are said to eat dreams.

Lance has two Pokemon with illegal moves. In Red & Blue, his Dragonite uses Barrier and his Aerodactyl uses Rock Slide in Gold, Silver, and Crystal. These Pokemon cannot learn these moves in-game without the use of a cheat device.

It is actually possible for a female Azurill to evolve into a male Marill. The reason for this is because Azurill and Marill have different gender ratios. Azurill have a 75% chance of being female, while Marill have only a 50% chance. Due to the mechanics that decide gender (a hidden value called the Personality Value) combined with this unique ratio difference, one in three female Azurill will change gender when they evolve.

The blue Pokemon mini was modeled after Wooper.

Porygon is the only Pokemon that can evolve at level 1 twice without actually leveling up.