1. Tentacruel
   Metapod
2. Poliwhirl
   Rattata

Metapod is commonly known as a Cocoon Pokémon, for its resemblance to a chrysalis. Metapod's pre-evolved state, Caterpie, looks like a caterpillar; and the evolved form, Butterfree, looks like a butterfly.

1. Primeape
   Beedrill
2. Machamp
   Charmeleon

Charmeleon is a Fire-type Pokémon and the evolved form of Charmander, one of the original three starter Pokémon. One noticeable difference between the two is that Charmeleon sports a spike on top of its head.

1. Graveler
   Fearow
2. Slowbro
   Nidorino

Graveler is number 75 in the Pokédex. No surprise here, but this Pokémon's diet is mostly made up of moss-covered rocks. With its distinct round shape, Graveler's preferred way to travel is by rolling.

1. Kakuna
   Mankey
2. Charmander
   Oddish

Mankey is a Fighting-type Pokémon, described as a pig-monkey type animal. At number 56, Mankey is the first Fighting-type listed in the Pokédex, and it is known for having superior footwork.

1. Ivysaur
   Butterfree
2. Zubat
   Psyduck

This Pokémon evolves from one of the original video game starters, Bulbasaur. Out of all the Generation I Pokémon, Ivysaur is the only one whose name starts with an I. The bud on its back is based on a Rafflesia flower.

1. Dugtrio
   Vulpix
2. Raichu
   Alakazam

With three heads making up this "trio" of a Pokémon, it's bound to have some impressive stats. It is the fastest Ground-type Pokémon — a pretty impressive feat for not having any feet!

1. Nidoran
   Persian
2. Wigglytuff
   Machoke

Wigglytuff may look cute, cuddly and not so tough, but beware of being sung to sleep by its pre-evolved form, Jigglypuff! Wigglytuff is exactly one meter tall, or about three feet.

1. Pidgeot
   Weepinbell
2. Wartortle
   Vileplume

Pidgeot is a bird-like Pokémon with two prior evolutions — Pidgey and Pidgeotto. Pidgeot is the only Pokémon with a total base stat equalling 469. In the newer series, it is capable of becoming Mega Pidgeot — a sort of fourth evolution of the Pokémon.

1. Spearow
   Nidoqueen
2. Poliwrath
   Venonat

Using a Moon Stone is what evolves Nidorina into Nidoqueen, with the original Pokémon being Nidoran (the female version). Nidoqueen and Nidoking are the only two Poison/Ground-type combination of Pokémon.

1. Pikachu
   Golem
2. Clefable
   Magnemite

Pikachu is one of Pokémon's most memorable and well-known characters, and is even the star of several Pokémon movies. Along with berries and apples, one of Pikachu's favorite foods is ketchup.

1. Diglett
   Clefairy
2. Kadabra
   Arbok

Clefairy is fairylike and pixielike, and it evolves into Clefable. Though Pikachu might be commonly known as the mascot of Pokémon, Clefairy was originally going to hold that place.

1. Ponyta
   Ninetales
2. Meowth
   Sandshrew

Meowth is easy to spot, with a shiny gold coin decorating its forehead, and it can evolve to Persian once it reaches level 28. Meowth was the first Pokémon to ever talk in animé.

1. Seel
   Zapdos
2. Electabuzz
   Drowzee

This Pokémon is based on the real world seal, with Seel more specifically designed to look like a newborn harp seal. Seel is not an Ice-type Pokémon, but it evolves to one who is — Dewgong.

1. Slowpoke
   Victreebel
2. Poliwag
   Blastoise

This lazy Pokémon is based on the salamander animal. Slowpoke's name was originally supposed to be "Slowmo." It is not known to have much intelligence and is often forgetful or unaware of what it is doing.

1. Charizard
   Gloom
2. Pidgey
   Growlithe

Growlithe may appear cat-like, but this Pokémon actually falls into the Puppy classification. The evolved form of Growlithe is Arcanine, who is said to be able to run over 6,000 miles in one day.

1. Aerodactyl
   Farfetch'd
2. Mr. Mime
   Haunter

In the television series, Mr. Mime is regularly seen helping Ash's mom at home. While the name might imply otherwise, not every Mr. Mime is male. Exactly half of all Mr. Mimes are female.

1. Arcanine
   Squirtle
2. Bellsprout
   Pidgeotto

Bellsprout is known as the Flower Pokémon, with two leaves, two roots and a difficult-to-miss bulbous head. Bellsprout gets its nutrients through the soil and from eating insects.

1. Gengar
   Scyther
2. Doduo
   Snorlax

Gengar is a Ghost/Poison-type Pokémon, with bright red eyes and a wide ghoulish grin. This Pokémon also has a nightmarish theory attached to it — that Gengar may be a shadow of Clefable.

1. Geodude
   Nidorina
2. Parasect
   Raticate

Although it has ratlike attributes, Raticate is considered a Mouse Pokémon. When Raticate is attacked, it stands on its back legs and lets out a loud shriek. Its hind feet are webbed, for swimming.

1. Mewtwo
   Cloyster
2. Gyarados
   Electrode

This Pokémon thrives in the water and is even large enough to carry trainers on its back. Gyarados's stats are improved at a comedic level from its one and only pre-evolved form, Magikarp.

1. Rhyhorn
   Mew
2. Meowth
   Lapras

The cry of Rhyhorn is exactly the same as Charizard's in the Pokémon games. Its evolved form, Rhydon, was the first Pokémon to be created. Rhyhorn's bones are said to be 1,000 times tougher than human bones.

1. Tauros
   Kingler
2. Dragonair
   Muk

Dragonair is a Dragon-type Pokémon, and the original name for it was "Dragyn." Its evolved form, Dragonite, is known to be very hard to find in the wild. Dragonair has the ability to change the weather.

1. Raichu
   Ditto
2. Rhydon
   Weezing

Ditto is quite the copycat, as this Pokémon can take the form of others in battle, depending on its opponent. To tell the difference between a Ditto and the real Pokémon, take a look at the eyes — the Ditto copycat will always have its original eyes.

1. Jynx
   Onix
2. Articuno
   Dodrio

Articuno is an Ice/Flying Pokémon that is in its final form, which means it doesn't evolve. Articuno is one of the three Legendary birds of Kanto, with the other two being Zapdos (Electric) and Moltres (Fire).

1. Hitmonchan
   Kangaskhan
2. Oddish
   Jolteon

When born, Kangaskhan already has a baby in its pouch. The baby will occasionally come out to play, but it should never be disturbed. A Kangaskhan, which resembles a kangaroo, will never evolve.

1. Magneton
   Gastly
2. Starmie
   Kabutops

This Pokémon is one of only two kinds (with the other being Oddish) to have a scientific name, which is "Kabutops maximis." Kabutops is a Water/Rock-type Pokémon and is known for swimming extremely fast.

1. Shellder
   Magikarp
2. Dragonite
   Voltorb

Voltorb may be confused for a Pokéball at first glance, which can be dangerous for curious Pokémon and trainers. It is the 100th Pokémon listed in the Pokédex. It is an Electric-type Pokémon, and it has the lowest Attack stats of all within that classification.

1. Caterpie
   Paras
2. Bulbasaur
   Tentacool

Paras is a Grass/Bug-type Pokémon. Paras has mushrooms known as "tochukaso" growing on its back, which are parasitic. The mushrooms survive by getting nutrients from the Pokémon's body.

1. Rapidash
   Jigglypuff
2. Machop
   Sandslash

Machop is the original form of the evolved Machoke, and then Machamp. Machop's entire body is made up of muscles that never tire, so he can keep fighting without the worry of cramping up.

1. Flareon
   Mankey
2. Horsea
   Hitmonlee

Horsea is — you guessed it — a seahorse-like Pokémon who lives in water. Horsea evolves to Seadra at level 32, and this evolved form is able to swim backward while looking forward.

1. Magmar
   Dewgong
2. Moltres
   Hypno

This blazing Pokémon is based on a combination of a duck and a reptile-like animal, and it's covered in a series of flames and fiery designs. It has spikes on its back that resemble those of an iguana.

1. Dratini
   Pinsir
2. Grimer
   Krabby

You'll find this Pokémon hanging out in coastal regions. Krabby uses its pinchers to help it balance when walking sideways. If it loses its pinchers in a Pokémon battle, they grow back quickly.

1. Omanyte
   Cubone
2. Poliwag
   Goldeen

Goldeen is a Water-type Pokémon that looks a lot like its commonly known animal doppelgänger, a goldfish. Goldeen has been nicknamed the "Water Queen," as its appearance resembles a fancy ballgown.

1. Abra
   Venomoth
2. Ekans
   Nidoking

The older this Pokémon gets, the longer it grows. You can find Ekans slithering through grassy areas. Ekans is a Snake Pokémon, which makes sense with its name, as "Ekans" spelled backward is "snake"!

1. Tentacool
   Seadra
2. Marowak
   Porygon

This Pokémon is the only one that needs to be traded twice for other Pokémon in order to evolve. Porygon is able to move freely throughout cyberspace. It is theorized that Porygon may be inspired by origami cranes.

1. Exeggutor
   Staryu
2. Seaking
   Squirtle

Exeggutor is a Grass/Psychic-type Pokémon. Exeggutor is the favorite Pokémon of Tsunekazu Ishihara, president of the Pokémon Company. One theory about Exeggutor is that its heads can fall off, creating the Pokémon Exeggcute.

1. Koffing
   Chansey
2. Eevee
   Jigglypuff

The Eevee family has more evolutionary relatives than any other Pokémon species. In Generation I, Eevee can evolve to Vaporeon, Jolteon or Flareon, depending on the type of stone used.

1. Golbat
   Venusaur
2. Golduck
   Weedle

Golduck is a Water-type Pokémon and the evolved form of Psyduck. It is easy to spot, with an allover blue color, webbed feet, one red gem dotting its forehead and four spikes atop its head.

1. Tangela
   Lickitung
2. Vaporeon
   Ninetales

Tangela is the only pure Grass-type Pokémon in Generation I. Tangela's entire body is made up of seaweed-like vines that never stop growing and move with the Pokémon whenever it moves.

1. Pidgey
   Kabuto
2. Exeggcute
   Omastar

Omastar is a prehistoric Pokémon with a beak-like mouth full of sharp points. Due to such a heavy shell preventing it from catching any prey, Omastar is thought to be extinct.