The Pokémon anime (formally called Pokémon the Series) has been following Ash Ketchum and Pikachu for over 24 years as they had many incredible adventures to discover new Pokémon and win battles.
Characters in Pokémon have grown and changed throughout their travels. Some Pokémon's growth was merely measured by their evolutions, like Ash's friendly Turtwig who became a steadfast Torterra. Pikachu's growth as a character has not been as obvious as Torterra's, but Pikachu still changed in many ways.
10 Pikachu Kept Getting Stronger
Ash's Pikachu has always been powerful. In fact, Pikachu's abnormal strength was the main reason that Team Rocket began pursuing Ash's Pokémon in the first place, which remains a constant conflict to this day. Many Pokémon had impressive achievements but Pikachu's power and Ash's creativity have made Pikachu the notable battler that he is today.
Early on, Pikachu defeated an entire flock of Spearow with a single Thundershock and later defeated Pikachu's own evolved form, a Raichu, during a battle against Gym Leader, Lt. Surge. Pikachu went on to conquer many more opponents and at the height of Pikachu's power, he beat the legendary Pokémon, Latias, in a rare double knockout.
9 Pikachu Got Weaker In Unova
Not long after Pikachu beat a Latias, Pikachu was unfortunately depowered by the legendary Pokémon, Zekrom, during the first episode of Pokémon the Series: Black & White. When Zekrom struck Pikachu with a bolt of electricity, Zekrom also removed most moves Pikachu had learned up to that point. Pikachu was defeated by a very young Snivy soon after losing his power. Pikachu's loss showed how weak Pikachu had become, since starter Pokémon like Snivy are only level 5 in the Pokémon games.
Pikachu did eventually regain most of his power by the end of Ash's adventures in Unova, and Pikachu has continued to get stronger as the series continued into new regions.
8 Pikachu Aged, Then Regressed, Just Like Ash
The Pokémon anime's canon is relatively consistent, with Ash typically remembering where he has been, who he has met, and which Pokémon he has caught. The show and movies rarely reference each other but are considered part of the same canon up to the 19th movie, which took place in a separate universe. Even though the Pokémon anime's canon is set, there was one major oversight in Pokémon 3: The Movie.
Pokémon 3: The Movie (2000) featured a short film titled Pikachu & Pichu, where Pikachu traversed a city to get back to a party that Ash was hosting. This party was meant to commemorate the first anniversary of Ash and Pikachu meeting, which means the party took place on Ash's 11th birthday. Despite Ash being 11 years old in Pokémon the Series: Gold and Silver (1999) as stated by this film, the Pokémon anime would later state that Ash was still 10 years old in the first episode of Pokémon the Series: Black & White (2012). Due to that canonical oversite, it would seem that Ash and Pikachu have both aged a year then regressed a year.
7 Pikachu Has Made Many Human & Pokémon Friends
Ash and Pikachu have made new friends with every new season of Pokémon. They may have begun the series with Brock, Misty, and their respective Pokémon in tow, but each companion was been replaced over time. Misty made way for May, Dawn, Iris, and Serena while Brock was replaced by Tracey, Cilan, and Clemont. They may have been Ash's friends first, but Pikachu also cared for them and successfully battled alongside Serena once while Ash was sick.
Besides his human friends, Pikachu has many Pokémon friends too. During downtime scenes between battles, Pikachu can be seen eating alongside other Pokémon like Brock's Geodude and Iris' Axew, or playing with any of Ash's various Pokémon. Pikachu has also been involved in a couple of romances, being the subject of affection for Dawn's Buneary's and having his own crush on a female Pikachu called Curly.
6 Pikachu Has Learned and Forgotten Moves
Pikachu has used numerous moves throughout the anime, beginning with Thunder Shock in Episode 1. Pikachu soon filled up his move list with Thunderbolt, Agility, and Quick Attack. His moves have fluctuated throughout the anime's run but Thunderbolt and Quick Attack have almost always been part of Pikachu's move-set. Pikachu's moves usually make use of his speed, like Agility and Quick Attack but they also use his Electric-Type abilities for attacks like Thunder, Volt Tackle, and Electro Ball. Pikachu also learned the Steel-Type move, Iron Tail, to deal with Gym Leader Roxanne's sturdy Rock-Type Pokémon.
Pikachu has also utilized the Z-Moves of Alola for incredible attacks like 10,000,000 Volt Thunderbolt, and while traveling in the Galar region, Pikachu transformed into the towering Gigantamax Pikachu form. Pikachu's new form let him use powered-up attacks like Max Steelspike, which was a giant version of Iron Tail.
5 Pikachu Decided Not To Use A Poké ball
Pikachu and Poké Balls are ever-present Pokémon imagery, but unlike Ash's other Pokémon, Pikachu never travels in a Poké Ball. Pikachu decided at some point, for unknown reasons, that he would never go back into his Poké Ball after the anime's first episode.
In that episode, Pikachu seemed to simply dislike being in a Poké Ball but in Pokémon the Movie: I Choose You!, Pikachu claimed not to use a Poké Ball because he always wants to be with Ash. The reasoning of "wanting to be with Ash" is probably true in the main Pokémon anime continuity too, but it was clearly not Pikachu's original reasoning.
4 Pikachu Finally Became Part Of A Champion's Team
Most Pokémon seasons have ended with Ash and Pikachu being demolished in the regional Pokémon League Tournaments. Many fans thought the finale of Pokémon the Series: XY would feature Ash's first win because of the efforts of Pikachu, Greninja, and the others, but Ash's Pokémon were defeated by Alain and his Mega Charizard.
This defeat was shocking to Pokémon fans, and they began to lose hope of Ash and Pikachu ever becoming champions. Just a few years later, Ash's previous failures were made irrelevant when he secured a victory in the first-ever Alolan Pokémon League Tournament. Ash had many Tournament losses over the anime's run and Pikachu was the only Pokémon to be involved in each one of them, but with the Alola victory, Pikachu finally became a champion too.
3 Pikachu Has Seen The World
So far, Pikachu has been to the Kanto, Johto, Hoenn, Sinnoh, Unova, Kalos, Alola, and Galar regions. Those regions are analogs for the real-life countries of Japan, the United States, France, Hawaii, and the United Kingdom, which is pretty impressive for a tiny electric mouse and is more than many real people see in a lifetime.
Besides Pikachu's travels in the main series, the Pokémon movies have led Pikachu to even more places, like independent kingdoms and mysterious islands. Pikachu has even time-traveled.
2 Pikachu Has Become Incredibly Famous In The Real World
Most Americans who are even somewhat familiar with Japanese culture, anime, or video games, are also familiar with Pikachu. The Pokémon craze of the '90s and early 2000s ensured that Pikachu was everywhere from cards, clothes, and figurines, to airplane wraps and parade balloons.
Pokémon's mainstream popularity waned for a bit but recently returned in full force. Pokémon cards had a resurgence of popularity during 2020 and 2021. The newest games (Pokémon Sword & Shield) are the third best-selling games in the series. The Detective Pikachu movie was incredibly popular in 2019. People love Pokémon again, and they love Pikachu too.
1 Pikachu Got Skinny
It was simply a change of design, but Pikachu has clearly become thinner since the '90s. Chubby Pikachu was an incredibly iconic design but when considering the range of motion and expression required of a main character, the skinnier design was probably the better choice to go with because it was easier to animate.
The chubby design was phased out by the mid-2000s but was eventually brought back in Generation 8 as Pikachu's Gigantamax form.