The next day brings two major events, the first being Ash’s battle with Pidgeotto, in which he flippantly disregards two of the most basic lessons of life as a Pokémon trainer: he tries a Pokéball without weakening Pidgeotto first (and I thought he’d learnt better after episode one), showing that he doesn’t actually understand how to catch Pokémon, and he tries to fight Pidgeotto with Caterpie (and reacts with abject confusion when Misty points out that “Pidgeotto is a bird; Caterpie is a worm; birds eat worms, Mister Pokémon Master!”) showing… not so much that he doesn’t understand the concept of a type advantage, more that he doesn’t even understand the concept of fighting.  Pikachu steps in to save his sorry butt and fries Pidgeotto into submission, and we quickly move on to the next big event of the day: Team Rocket’s appearance.  They’ve decided to follow Ash and steal Pikachu, since the Viridian City Incident has convinced them that, in Meowth’s words, “[Pikachu’s] powers exceed its evolutionary level” (a fascinating comment in itself, but one I don’t have time for now).  Ekans and Koffing attack Ash together, so Misty offers to step in to even the odds, but Ash refuses because the Pokémon League rules say that battles are one-on-one.  Never mind that he’s being mugged by notorious criminals; the rules say that he can only use one Pokémon and he will defend those rules with Pikachu’s life if need be.  Long story short, Caterpie manages to overcome Ekans, Koffing and Meowth with a particularly well-executed String Shot, of all things, and Team Rocket are forced to retreat.  This victory prompts Caterpie’s longed-for evolution into Metapod, and an observation from Ash’s Pokédex that no other Caterpie on record has ever evolved so rapidly.  Ignoring for the moment how the Pokédex could possibly know how mature Ash’s Caterpie was when he caught it, this is the first of many indications given in the anime that evolution isn’t just about reaching a certain level, as in the games; there’s a psychological component as well.  I think Caterpie’s remarkably fast evolution is implicitly a result of his unusual ambition; it took less to make him evolve because he was more ‘ready’ for it, mentally speaking, than most Caterpie.  Basically, he’s a little Pokémon with big dreams, and being with Ash is going to help fulfil them.

In the next episode, Challenge of the Samurai, Ash is accosted by a weird kid in samurai gear while trying to catch a wild Weedle.  And when I say “accosted” I mean he nearly gets cut in half by an honest-to-goodness steel katana.  This kid… oh, this kid… I don’t think he even has a name; if he does, he never tells Ash and Misty what it is, so I’m just going to call him Sammy.  Sammy lives in the darkest part of Viridian Forest with his Bug Pokémon and challenges other trainers as they pass through.  I don’t know why.  He just does.  He doesn’t seem to be interested in travelling or collecting badges, in fact he has a permanent cabin deep in the woods, so the only conceivable reason for him to be interested in getting stronger is so he can make himself more of an inconvenience to travellers.  The kid’s a friggin’ random encounter (“random” being the operative word).  Anyway, he calls Ash “dim-witted and clumsy” for letting the Weedle escape, Ash protests that it was Sammy’s fault for coming at him with a sword (this is supposed to be the beginning of a point the episode is making about Ash learning not to blame his failures on others, but I can’t help but feel Ash is in the right here), and they quickly engage in battle.  Pidgeotto doesn’t manage to make much of an impact on Sammy’s Pinsir because Ash has been overworking him and he’s done for the day, so Ash turns to Metapod.  Only after he makes this choice does it occur to him that Metapod can’t actually fight, but luckily for him evolution didn’t make his Caterpie any less exceptional, and Pinsir injures itself trying to crack Metapod’s tough shell, forcing Sammy to recall it.  This leads us into one of the most awesome Pokémon battles of all time, an epic struggle of titans to be remembered by our children’s children for aeons to come: Metapod vs. Metapod.  I really don’t know what Ash and Sammy are trying to prove in this battle.  It conveys rather effectively, though, that both of them are astonishingly stubborn.  Their Metapod keep staring at each other and using Harden for some time – possibly hours – until the battle is interrupted by a swarm of wild Beedrill, apparently the friends of the Weedle that escaped Ash earlier.  Metapod is snatched up by a Beedrill before Ash can recall him, and they all have to leg it back to Sammy’s cabin to escape being stabbed to death.

Ash eventually goes to get Metapod, whom they saw on the way to Sammy’s cabin sitting at the base of a tree filled with Kakuna.  This is problematic because Kakuna will apparently evolve into Beedrill at the slightest provocation, but Ash is able to reach Metapod alive, despite Team Rocket’s antics causing the Beedrill to become aggressive again.  Metapod, unsurprisingly, seems very hurt that Ash allowed him to be taken in the first place, which Ash initially blames on Sammy but soon admits was his own fault, giving a heartfelt apology.  The resulting surge of loyalty prompts Metapod to jump into the path of a Beedrill trying to skewer Ash, violently splitting his shell open… which catalyses his final evolution into Butterfree.  Butterfree pacifies the whole swarm with Sleep Powder, Sammy is sufficiently impressed, and Ash, Pikachu and Misty get to move on to Pewter City.

In Challenge of the Samurai we see Pokémon evolving out of transitional states, ones which are never supposed to be long-term, so the conclusions we can draw from it aren’t necessarily all-inclusive, but there’s no harm in speculation.  Ash’s Pokédex claims that Metapod evolve into Butterfree one week after evolving from Caterpie, which sounds way too long, but since Ash tells Brock in the next episode that he’s been with Pikachu for two weeks already, it’s probably about right.  Regardless, it’s clear that Metapod didn’t evolve because he was ready; he evolved because he needed to, as do all the Kakuna we see evolving in this episode, which comes back to the idea of evolution having a psychological component in the anime: at some point, despite being physically able to evolve, Metapod and Kakuna still need some kind of stimulus to kick things off.  It’s interesting that Metapod doesn’t evolve when he’s first snatched away by the Beedrill, because he doesn’t actually ‘gain experience’ between there and the end of the episode, and judging by his reaction when Ash comes to save him I think it’s because he felt abandoned when Ash ran away without him and may have given up hope (one of his persistent character traits in the episodes that focus on him seems to be that he has self-esteem issues).  It’s the renewed feeling of being in a partnership with his trainer, and the associated swell of devotion, that eventually makes a Butterfree of him.