There are several games across the Super Smash Bros. franchise, and of course, there are even more fighters. Characters tend to change with each new installment, for better or worse, but very few characters have been consistently viable throughout every Smash game they've been in. One character that's agreed to be the best consistent character is Pikachu, the mascot of Pokémon.
Pikachu has always had great tools in each Smash game. And now, in Super Smash Bros. Ultimate, he's a strong contender for the very best character of them all. This makes it a pain for many to even see the character on screen, but fighting him doesn't have to be a complete chore. Figure out his strengths and weaknesses by reading ahead and seeing what you can do to take him down.
Pikachu's Strengths
Pikachu's best strength is his aerial game. He has many tools that allow him to apply lots of pressure in the air. A major contributor to this is each of his aerials being low on startup and endlag, allowing him to press buttons consistently and execute combos in many situations. Their multi-hit nature (excluding his Up-Air) also plays a part in this and helps him win in edgeguarding scenarios due to how active they are. His edgeguarding capabilities are exemplified by his Neutral-B being an angled projectile that moves along surfaces. He also has two spikes in his DAir and Down-B, the latter of which is great for catching high recoveries.
He's also very hard to hit. His hurtbox is already smaller than most of the cast. It becomes even harder to hit him at times due to his ability to "pancake," which refers to the flattening of a hurtbox to the point where attacks that hit most characters will miss. His overall speed and mobility also play a part in this, with his dashing speed and jumps being quite high. This is also why he's hard to edgeguard. Recovering to the stage is very easy, thanks to the flexibility with which he can make it back, with his Side-B being great for horizontal recovery. Up-B allowing him to move quickly in two directions, makes his recovery options more versatile. These tools are also why his disadvantage state is pretty great since he has a variety of ways to maneuver out of troubling situations.
Pikachu's Weaknesses
Pikachu has a few weaknesses, and it's hard to consider its major flaws. The first is his lack of range. While his Forward Smash is an active and disjointed attack, the rest of his normals are very minimal in range, being either very small disjoints or not disjointed at all. His Neutral-B makes up for this, but it makes his approach one-note at times as he needs to rely on it to safely cover himself. An opponent that can get around this can make Pikachu work harder to get in.
Another weakness is his inability to kill — Pikachu has to rely on edgeguards with extensive combos to take stocks. That being said, his moves combo so well due to the multi-hit properties and lack of launch power they have. So, when a character ends up living his edgeguards, Pikachu will struggle to kill onstage with his normals and throws. His Smash attacks work fine, with some of them being quick, along with dash attacks, but all of them are either very unsafe or inconsistent with their hitboxes. This isn't an issue on its own, but it makes survivability a bit hard for Pikachu since he himself gets killed easily for being very light.
Strategy & Counterplay
You'll have to deal with his extensive combos and multi-hit attacks when fighting Pikachu. DI/SDI will be your best friend in this matchup. Of course, you can't use this on every combo, especially the ones where he'll drag you down. But it will be especially useful to escape low to mid-percent combos and some kill confirms, such as Up-Throw into Down-B. Make sure you don't always use the same DI in the case of kill confirms since Pikachu can still find the stock if he predicts it.
You'll want to make it hard for Pikachu to apply pressure in neutral. A major part of this involves dealing with his Neutral-B. This is mostly character-dependent, as some have tools better suited for it than others. In any case, you'll want to mix up your answers so he can't exploit how you respond to them. A solid choice across all characters is to perfectly shield it and go from there. Aside from that, make sure to stay mobile, don't play too defensively, and not be afraid to challenge him. The multi-hit nature of Pikachu's moves means that pretty much any single-hit attack will leave him more damaged than you in a trade scenario.
Continuing the topic of Pikachu's combos, you'll probably find yourself being carried offstage with them, especially at the lower percents. While this is a dangerous situation, using your resources will most likely get you killed here. Make sure to save your resources until the combo ends. If you use them up too early and Pikachu manages to catch you in his combo still, you're going to have a much harder time making it back to the stage.
Good/Bad Matchups
Pikachu outright wins against a vast majority of the characters. Characters he especially wins against are those that can't deal with his pressure very well. This includes both characters he can combo and characters with slower frame data overall. For the former criteria, avoid using characters like Donkey Kong, King K. Rool, King Dedede, Incineroar, and Ganondorf. For the latter criteria, Byleth, Simon, Hero, Robin, and Bayonetta aren't great picks against him.
Since he wins against the vast majority of the cast, there are very few that he loses against, if any. These characters are simply those that can deal with his Neutral-B, usually by absorbing it. Reflecting on it or using other means to avoid it works too, though. It's because of this that Mr. Game & Watch, Ness, Olimar, Peach, and Mario are good against him.