Caterpie is relatively rare on Route 2, with a 5% encounter chance. Caterpie is very common in the Viridian Forest, with a 40% encounter rate. Metapod has either a 5% or a 10% encounter rate in Viridian Forest, depending on which version you’re playing (5% for FireRed, 10% for LeafGreen). Caterpie has a 20% encounter rate on Route 24 and Route 25. Metapod has a 4% encounter rate on Routes 24 and 25 in LeafGreen and a 1% encounter rate on the same routes in FireRed.
Many Nuzlockers disregard the Caterpie line as “derps” or “early game bug box fodder”. However, Butterfree’s diverse movepool and fast evolution speed can make it a great team member, especially in the early-game. Many claim that Butterfree should not be used late-game, and while their claims of low BST and bad typing are valid, with the right TM support it can go through to the Elite Four. Caterpie’s early availability and common encounter rate makes it very likely that you will encounter one before Brock. Butterfree’s stat total can be a little bit underwhelming, but keep in mind that it will be fully evolved at the time that most Pokémon are around 10-15 levels away from evolution. Its crippling weakness to Rock means that you should definitely switch it out against Rock-types that it can’t OHKO with Confusion. Butterfree can also lead a support role with its many powder moves. These moves, coupled with its Ability Compoundeyes, can make it easy to cripple an opponent. Overall, Butterfree is a choice you should definitely add to your team, will be amazing at the start, and keep pulling its weight nicely throughout the game.
Rival (Route 22, optional): Metapod is not a great choice for this battle, as this is the stage it will most likely be. Keep it away from Pidgey and Charmander. However, against Squirtle, its great defense stat can help you defeat it without too much trouble. Against Bulbasaur, it is possible but by that time you probably have a Flying-type to help you out. Bulbasaur’s Leech Seed may also be an issue.
Gym #1 - Brock (Pewter City, Rock-type): In the event that you have a Bulbasaur or a Squirtle, Butterfree is completely unnecessary in this battle. If you picked Charmander, however, Butterfree can be a huge help in this battle. While its Bug/Flying typing may discourage you from using it, Geodude’s and Onix’s low Special Defense allows Butterfree to KO them quickly with Confusion before they can retaliate with Rock Tomb. In fact, Geodude doesn’t even have a Rock-type attack! If it is level 15, it can Sleep Powder the opposing Pokémon first for extra safety.
Rival (Cerulean City): Butterfree can be easily killed by the rival’s Charmander and underleveled Pidgeotto, so you should keep it away from these two Pokémon. It can kill the Rival’s Abra, but any Pokémon that knows a damage-dealing move can do this. It fares well against Squirtle and Bulbasaur, especially since it doubly resists Bulbasaur’s Vine Whip and has SE Confusion. Against Rattata it can go for an easy 2HKO with Confusion, and you can apply Sleep Powder if you are afraid of Butterfree’s low Defense.
Gym #2 - Misty (Cerulean City, Water-type): Butterfree should only really be used in this Gym if you have no better options. While it doesn’t have any distinct disadvantages, it doesn’t really have any advantages either. Against Staryu, it can sleep it and then KO it with multiple confusions. Starmie should be faced by another Pokémon, as it resists Butterfree’s only viable attacking move, Confusion.
Rival (S.S. Anne): Butterfree is still easily killed by Charmeleon or Pidgeotto, and is now in danger due to Raticate’s Hyper Fang. If you have nothing better to defeat Raticate with, you can attempt the Sleep Powder strategy mentioned earlier. Against Wartortle, Sleep Powder + Confusion should be able to KO it without too much trouble, and Super-Effective Confusion will easily defeat Bulbasaur. Against Kadabra, it would not be strategic to use Butterfree due to its only viable attacking move being resisted by it. If you have kept Tackle, you can potentially put Kadabra to sleep and go for the many-hit KO with Tackle, but only if you’re rather patient.
Gym #3 - Lt. Surge (Vermilion City, Electric-type): You should keep Butterfree well away from this gym. Any Electric-type move from Lt. Surge’s powerful Pokémon will be able to OHKO or 2HKO it. By this time, you will likely have a Ground-type *cough*Diglett*cough*, so Butterfree is unnecessary.
Rival (Pokémon Tower): As usual, Butterfree cannot stand up against Charmeleon or Pidgeotto. It is wise to not use it against Growlithe, either. It may be able to KO Gyarados after Sleep Powdering it, but Thrash may OHKO it back even without critting. Only use Butterfree against it if you have no other option. Against Exeggcute and Kadabra, it should not be used due to them resisting Confusion. It can still defeat Ivysaur without too much trouble by Confusion-ing it to death. Finally, it can reliably defeat Wartortle by using Sleep Powder in combination with Confusion.
Giovanni (Rocket Hideout, Ground-type): Against Rhyhorn and Onix, Butterfree is in way too much danger of being OHKO’d by a strong Rock-Type Move. Similarly, it should not be used against Kangaskhan due to Butterfree’s low Defense and Kangaskhan’s Mega Punch and high Attack.
Gym #4 - Erika (Celadon City, Grass-type) Butterfree can defeat Vileplume and Victreebel easily by resisting their strongest attacks and retaliating with Confusion. Tangela may not be weak to Confusion, but it has very low Special Defense and can’t really damage Butterfree, allowing for Butterfree to make a clean sweep of this Gym Leader.
Gym #5 - Koga (Fuchsia City, Poison-type): By this time, you should have Psybeam/Psychic for Butterfree, allowing it to OHKO Koga’s Koffings after outspeeding them. Against Muk and Weezing, it can reliably kill them by Sleep Powdering and then blasting them with strong Psychic-type moves; it is better to have Psychic for this purpose, though, as the 2HKO may be impossible otherwise.
Fighting Dojo (Saffron City, Fighting-type): Butterfree utterly decimates this excuse for a gym. Assuming you don’t OHKO both Hitmons with Psybeam/Psychic, it quadruple resists their Fighting-type moves. And there’s no need to be afraid of super-effective Thunder/Fire/Ice Punch from Hitmonchan’s base 35 Special Attack.
Rival (Silph Co.): As always, keep Butterfree away from Charizard, Growlithe, and Pidgeot. It is also still unable to do any real damage to Alakazam or Exeggcute. It can still defeat Venusaur with Psybeam/Psychic, and can Sleep Powder + Psybeam/Psychic Blastoise if necessary. Gyarados’ strong physical attacks should deter use of Butterfree against it.
Giovanni (Silph Co., Ground-type): Butterfree will be able to one-shot Nidorino with whatever Psychic move you currently have on it. Against Nidoqueen, it can OHKO or 2HKO with Psychic but with Psybeam it may need two or more hits. You should keep it away from Rhyhorn as it will die to its Rock Blast. It wouldn’t be very smart to put it up against Kangaskhan because of Kangaskhan’s strong STAB physical attacks coupled with Butterfree’s low Defense.
Gym #6 - Sabrina (Saffron City, Psychic-type): Butterfree will be able to OHKO Sabrina’s Venomoth with Psychic. Unless you have trained it to 47 for Silver Wind, it is recommended not to use Butterfree against her Psychic-types due to their high Special Defense and resistance to Butterfree’s Psychic-type attacks.
Gym #7 - Blaine (Cinnabar Island, Fire-type): Keep Butterfree away from this gym at all costs. Any strong Fire attacks from the opposition, and you’re down one Butterfree.
Gym #8 - Giovanni (Viridian City, Ground-type): Giovanni leads with Rhyhorn. That should be enough explanation right there. Against the Nidoroyalty, Butterfree can hold its own with strong Psychic attacks. Rhyhorn #2 is the same as Rhyhorn #1 in terms of whether you should send out Butterfree. Butterfree is immune to all of Dugtrio’s powerful attacks, so it can safely OHKO it. If your Butterfree has Giga Drain, it may be able to take on and one-shot the Rhyhorns, but it’s rather risky.
Rival (Route 22, pre-Elite Four): As always, Pidgeot, Growlithe, and Charizard should all be avoided by Butterfree. By this time, you will have Silver Wind which will OHKO Exeggcute, and do serious damage to Alakazam. Don’t let it fight Rhyhorn, as it is a Rock-type. Against Gyarados, it is wise not to use Butterfree due to its poor physical defense. It will be able to reliably take out Blastoise with Sleep, and as always, it will resist anything Venusaur throws at it and retaliate with Psychic attacks.
Elite Four Lorelei (Indigo Plateau, Ice-type): Butterfree should stay out of this battle. A strong Ice Beam or Blizzard could do some major damage to Butterfree. Against Slowbro, it could use Silver Wind to attempt to damage it, but it is wiser to just use another Pokémon. Slowbro has a massive Defense stat, so Silver Wind might not even be able to score the 2HKO.
Elite Four Bruno (Indigo Plateau, Fighting-type): Against Bruno’s Onixes it would be better to just use a Water or Grass-type. Butterfree can easily take out any of his Fighting types to do its Psychic attacks and double resistance to Fighting. Watch out for Machamp and Hitmonchan, though, as both have Rock Tomb which will kill you in an instant if they wake up. Sleep Powder + Substitute is recommended here, to stay on the safe side.
Elite Four Agatha (Indigo Plateau, Poison-type): Agatha’s entire team is frail Poison-types. As long as you outspeed, you should be able to 2HKO or 3HKO any of her teammates with Psybeam or Psychic, meaning that if you use Sleep Powder first, you will be safe unless it misses. Be careful against her Golbat if your Butterfree has low speed, however, as it can retaliate with Air Cutter.
Elite Four Lance (Indigo Plateau, Dragon-type): It is too risky to send Butterfree against Gyarados for the same reasons it is in any rival battle. It won’t have too much trouble KOing Lance’s two Dragonairs with Sleep Powder + Psybeam/Psychic if you have nothing better. Against Dragonite, the risk of Hyper Beam OHKOing it is too great to use Butterfree unless it is an emergency. Aerodactyl is a Rock-type, don’t even think about using Butterfree!
Champion Rival (Indigo Plateau): Against Pidgeot, Charizard, Arcanine, and Gyarados, Rhydon, it would be suicidal to use Butterfree. Venusaur can be killed easily with strong Psychic-type attacks. Blastoise is killable with the Sleep Powder + Psychic strategy. Against Exeggutor, a Silver Wind is more than enough to OHKO. You can try to use Silver Wind on Alakazam, but it may counterattack for a lot of damage with a strong Psychic.
Caterpie starts out with Tackle and String Shot, which are useful for leveling extremely early-game but should be deleted ASAP. As a Metapod, it learns Harden, an extremely crappy move. When it finally evolves into Butterfree, it learns Confusion, a move you should keep until you can replace it with a stronger Psychic-type attack. At level 13, it learns PoisonPowder, which you can keep for a short time but isn’t very good due to Butterfree not having the defenses for a staller. At 14 and 15 it learns Stun Spore and Sleep Powder respectively, and Stun Spore should be deleted for Sleep Powder as Sleep Powder has a more reliable not-moving rate. At 18, it learns Supersonic, which can be useful at times, but sleep is usually a better option than confusion. At 23, it learns Whirlwind, which is situational and shouldn’t be added to your moveset unless you have a specific purpose in mind. At 28 Gust is learned, which may be STAB but it is also physical in this generation, and it has a very low base power. At 34 Psybeam is learned, which should replace Confusion. Safeguard, learned at level 40, can be a very useful move if used properly. At 47 it learns Silver Wind, which is STAB, can cover Psychic-types, and has a chance of boosting Butterfree’s stats.
Butterfree learns a few useful moves via TM. TM29 Psychic, found in Saffron, can be a very useful replacement for Psybeam. TM19 Giga Drain, given as a reward for defeating Erika, can be useful if you need HP recovery. On Route 9, TM40 Aerial Ace can be found, giving Butterfree some reliable Flying STAB. Finally, TM10 Hidden Power, which can only be found via Pickup, can be useful for extra coverage, assuming Butterfree has a high Hidden Power base power and a good type.
Via Tutor, the move Dream Eater can be a very useful recovery move for Butterfree. You will likely be Sleep Powdering everything you can’t OHKO, and therefore Dream Eater won’t be as situational as you think. It is also complemented nicely by Substitute, which will make Butterfree almost impossible to hit.
Minimum stats are calculated with 0 EVs, IVs of 0, and a hindering nature, if applicable.
Maximum stats are calculated with 252 EVs, IVs of 31, and a helpful nature, if applicable.
Caterpie Line Ratings
What Nature do I want? Natures that raise Special Attack are optimal, so aim for Modest, Mild, Rash, or Quiet. Since Butterfree can’t take a hit too well, Mild and Rash may be inferior to the other two, since they lower one of Butterfree’s defensive stats. Quiet is second best, but it lowers Butterfree’s already unimpressive speed, which could be an issue at times. Modest is probably going to be the best Nature Butterfree could have, but keep in mind that it lowers the power of moves such as Gust and Silver Wind. This shouldn’t be too big of a problem, though, as special-based Psychic-type moves will be Butterfree’s main way of attacking.
At what point in the game should I be evolved? Before Brock if you picked Charmander, anytime before Mt. Moon if you didn’t. It’s worth the time you spend grinding to evolve it as quickly as possible, though.
How good is the Caterpie line in a Nuzlocke? The Caterpie line is one of the most frequently used Pokémon in Nuzlockes, and for good reason. It has access to a multitude of status moves, including Sleep Powder, which has its annoyingly low accuracy boosted to a near-perfect 97.5% by the Ability CompoundEyes. Butterfree’s Psychic-type moves, such as Confusion and Psybeam, are very good for whittling down the HP of sleeping opponents, and have very good coverage in-game just by themselves. Unfortunately, Butterfree’s painfully low Attack stat discourages use of either of its STABs. Despite its frailty and very low stats for a fully-evolved Pokémon, Butterfree is one of the better Pokémon you can use in a Nuzlocke of the Kanto remakes.