Explosion is the strongest move in GSC. It typically allows the user to OHKO whatever doesn't resist it, even with only moderate Attack backing the move. Furthermore, in GSC, you're generally not going to see very many attempts to predict Explosion unless the Pokémon using it doesn't have any way to harm a particular Pokémon resistant to it, which makes using Explosion to take out specific walls surprisingly reliable despite the obvious risk inherent with fainting one of your own Pokémon.The mechanics of Explosion make it amenable to multiple different uses: obviously, Explosion is useful offensively, but it is also effective as a defensive move, or even for achieving some more subtle tactical advantages. However, despite its broad usefulness and surprising reliability, Explosion is not an automatic win button by any means. There are effective ways to combat the use of Explosion to ensure that you end up on the winning end of your opponent's attempts to trade Pokémon. Knowing how to both use and combat Explosion is vital knowledge for success in GSC.
Explosion is extremely strong. It has a Base Power of 250, and has the added effect of halving the opponent's Defense stat, thereby effectively making it 500 Base Power. This halving of Defense always occurs even on a critical hit, which will otherwise ignore stat changes, Reflect, and burn if your Pokémon's Attack stage is lower than your opponent's Defense stage. A similar move, Selfdestruct, has 400 effective Base Power, but is often seen on Snorlax which, after STAB, has an effective 600 Base Power attack in its pocket. To put that in perspective, one Snorlax's Selfdestruct is stronger than two Thick Club Marowak's Earthquakes. Explosion also has the obvious effect of causing the user to faint. However, unlike in later generations, if the Exploding Pokémon moves first and the opposing Pokémon survives the attack, the Pokémon that was to move second will not be able to make a move that turn. Consequently, there will also be no poison, burn, or Leech Seed damage assessed for the surviving Pokémon during that turn, although Spikes damage will still be assessed for the switch-in to replace the Exploder, and unlike in DPP and later generations, Leftovers recovery will still be assessed for both Pokémon after the switch.
The most obvious use of a move with effectively 500 Base Power is for wallbreaking. However, there is a little finesse required to make sure you get the most out of Explosion. Generally, it's best to use a strategy known as bait Explosion, whereby your Exploders bait certain Pokémon that also wall or check a sweeper that you are running into switching. For example, a Pokémon such as Charizard is countered by Starmie, but Cloyster, thanks to Spikes, can frequently bait Starmie into switching in to spin away Spikes and then subsequently Explode on Starmie to KO it and open up a Charizard sweep. Growth Vaporeon is another sweeper that benefits greatly from Exploders KOing its counters; Exeggutor is a common Exploder that baits and Explodes on Sleep Talk Zapdos looking to absorb Sleep Powder, Gengar baits and Explodes on Sleep Talk Raikou looking to absorb Hypnosis and tank BoltBeam coverage, and Steelix baits Suicune, survives a Surf, and OHKOes with Explosion after a Curse. In general, a good offensive Exploder must have some way to force its target to switch in without risking a Pokémon that resists Normal from easily switching in. Sleep-inducing moves and attacks that hurt said Pokémon are very helpful in accomplishing this.
Explosion is also very useful from a defensive standpoint, primarily in terms of preventing a sweep. Sweepers such as Belly Drum Snorlax, Growth Vaporeon, and Pokémon that have been passed Agility boosts on a Baton Pass team can instantly end a game if one is unable to KO them swiftly. In this case, Explosion takes out these boosted Pokémon and saves the game. One of the better defensive Exploders is Cloyster, which outspeeds andKOesBelly Drum Snorlax, Quagsire, and Clefable,survivinghits from all of them at +6 (useful if they have an Agility boost), and outspeeds and KOes Growth Vaporeon with Explosion. Another good defensive Exploder is Forretress, for many of the same reasons, although it fails to outspeed Clefable or Vaporeon. Gengar is also a good defensive Exploder, as it can outspeed and Explode to KO fast threats such as Tentacruel, Charizard, and Snorlax even if it has an Agility boost under its belt.
One of the more subtle tactical uses of Explosion is gaining free turns. Because Explosion prompts aswitch inafter the user faints, even if you don't KO the foe, you still get an opportunity to switch a Pokémon in for free. In this sense, Explosion functions somewhat like U-turn in later generations, although it certainly isn't something you want to just spam in GSC. Also, if your Explosion goes first, even if you fail to OHKO the foe, the target will be left at very low health and unable to move because of the mechanics of GSC. This can be useful for effectively gaining two turns against a slower foe like Snorlax.
Sometimes mispredicting an Explosion can be just as bad as taking an Explosion. You can use this to your advantage with an Exploder by judiciously choosing to not explode. Most commonly, this is seen with Cloyster, which can punish a foe for switching out a boosted Belly Drum Snorlax or Growth Vaporeon for a Normal-resistant Pokémon by using Surf instead of Exploding. This is also often utilized by Exeggutor, which can spam moves such as Psychic and Sleep Powder against an active Zapdos that, depending on the situation, might be deathly afraid of taking an Explosion by virtue of being the only remaining counter to a threat such as Vaporeon or Heracross.
If nothing else, Explosion is generally good for just simplifying a game quickly. Because most good Exploders dissuade Pokémon that resist Normal from switching in, it's a fairly reliable way of getting rid of annoying pieces on your opponent's side and transitioning to a simple endgame. Trading down is a concept commonly seen in chess when a player has a material advantage and/or wants to simplify the game to avoid giving theiropponent an opportunity to develop a crazy tactical attack, and using Explosion to achieve the same effect in GSC is very sound strategy.
The main role of Cloyster is setting Spikes most of the time, but Cloyster is also a very effective Exploder on top of it all. Because of its role as a Spiker, it tends to bait Starmie and Explode on it without much trouble at all. Normally, Starmie is relegated solely to controlling Spikes, but it also checks a few niche threats such as Charizard and Machamp, and it's also pretty annoying for Ground-types to deal with, so even without Spikes it is valuable to be able to remove Starmie with Explosion. However, Cloyster is not very good at KOing Electric-types because, although it does a good job of baiting them, it has to catch them with a very risky Explosion on the switch. Cloyster also struggles to fight its way past Explosion-immune Ghost-types, although with enough Surfs on the switch, Cloyster can prevail.
Cloyster also has a pretty decent Speed stat, a Defense stat that allows it to tank Snorlax's blows, and a typing that allows it to tank Vaporeon's Surf. This combination makes it an extremely good defensive Exploder, as it is faster than the two most common setup sweepers in GSC and can even afford to take a hit when bluffing if the opponent calls that bluff.
Clamp is not a standard move on Cloyster, but it helps a lot with keeping Cloyster's Explosion targets in place. It doesn't help with Electric-types, obviously, but it eliminates Cloyster's need to bluff Explosion and instead simply traps risk-taking Snorlax and Vaporeon to ensure the KO. It also traps Starmie in the event that the opponent reads your team and decides they really need it, although most opponentswill look at Starmie clearing Spikes while being Exploded to death by the Spiker and think "mission accomplished."
Exeggutor gets Sleep Powder, which tends to draw Sleep Talk users like Zapdos and Raikou in. This is how Exeggutor gets good Explosions in spite of the Pokémon that resist Normal (Skarmory and Tyranitar) that match up well against it. However, despite its poor coverage, it often can have everything it needs to keep these Pokémon out: Giga Drain + Hidden Power Fire on a 3 attacks set thatforgoesa status powder keeps both Tyranitar and Skarmory out of its face. Exeggutor can also use healing from Leech Seed, Synthesis, or Giga Drain to stick around just long enough to Explode, use its typing to tank just enough hits to get an Explosion off, and spread paralysis with Stun Spore. Basically, Exeggutor is a great Exploder because it has so many ways to stick around and punish an opposing team for not just staying in and attacking with their Explosion-vulnerable Pokémon. Just don't let this thing take status; poison will put it on a timer and make its Explosion way more predictable, and paralysis might ruin your attempts to pull the trigger and leave you with a weakened, useless husk of a Pokémon.
Exeggutor can also be a fairly decent defensive Exploder, as it outspeeds Snorlax and can tank hits from troublesome Vaporeon and Zapdos, although it does have a couple problems on this front. The first is that its Explosion is fairly obvious when used defensively by Exeggutor; it cannot survive a Belly Drum Snorlax's Frustration, and because it is outsped by Vaporeon and Electric-types, if it doesn't pull the trigger quickly it could find itself in a situation where it is outsped and OHKOed. Being able to bluff the Explosion is a pretty important part of being a good defensive Exploder, as otherwise you tend to waste Explosion because the risk of not pulling the trigger is losing the game. Exeggutor also struggles as a defensive Exploder because it just isn't a great defensive Pokémon; ithard wallsvery little and functions primarily as an offensive second look, so it's more something you use to punish your opponent for playing too predictably rather than something you want to rely on to hold off the Mongol horde in the clutch.
Exeggutor is mostly held back as an Exploder by its limited defensive abilities. Its typing is good, but it's a primary check to nothing, second look to all, so don't expect to switch Exeggutor in willy-nilly to threaten to Explode, offensively or defensively. Even against threats it looks like it should absolutely cream, such as Machamp and Marowak,Exeggutordon't necessarily force them out with Psychic or Giga Drain because they can hit it back with Hidden Power Bug. Therefore, it is often forced to Explode on them and other threats that Exeggutor seems like it should be countering pretty hard, even though it seems like it should be able to force them out and use itsExplosion for another purpose, such as taking out Zapdos.
It's fast. It gets scary BoltBeam coverage to punish switching around. It has plenty of other aces in the hole such as Fire Punch, DynamicPunch, and Hypnosis to prevent Normal-resistant Pokémon from feeling comfortable about switching in, and Mean Look to trap its bait and guarantee a good Explosion. Gengar is basically the ultimate Raikou lure, making it a crucial offensive Exploder for most teams, as eliminating Raikou makes it much easier to generate offensive pressure with one's own Electric-type. However, there is some finesse to using Gengar to Explode on Raikou; it's slower, 2HKOed by Thunder, and normally doesn't OHKO with Explosion in return (the minimum damage 86% against most Raikou, 90% against Raikou with Hidden Power Water, and 92% against the rare Raikou with Hidden Power Grass), so unless you plan ahead and make sure Raikou is weak enough to be taken out (and preferably paralyzed so you don't have to take a big hit or risk it using Reflect to neutralize your Explosion), Raikou might barely survive and use its ridiculous Speed to use Rest next turn, thereby negating that Explosion!
Apart from Raikou, Gengar also targets Umbreon, Blissey, Quagsire, Snorlax, and Zapdos with its Explosion. However, all of these threats take a ton from Explosion, but are not OHKOed. Snorlax and Umbreon are especially resilient against Gengar's Explosion, taking 81% and 77% maximum damage, respectively. Again, it's important to have these targets weakened before you pull the trigger. Gengar also targets Starmie looking to stay in tousePsychic after a successful spinblock attempt, and this is actually one of the few Explosions that is guaranteed to OHKO, so feel free to Explode away when you see this opportunity.
As far as defensive Explosions are concerned, Gengar is mostly an offensive Pokémon, but it's pretty good at taking out DrumLax, although it's not quite strong enough to get really good damage against a +1 CurseLax when needed (Explosion will only do 45-52% damage). It can, however, outspeed a DrumLax with an Agility boost that has been Baton Passed from Jolteon, making it a great last line of defense against a Baton Pass sweep. Gengar can also Explode onaVaporeon that stays in expecting to tank a Thunderbolt and OHKO with a boosted Surf.
This thing is a powerhouse, although it technically uses STAB Selfdestruct and not Explosion. On top of its raw power, because Snorlax is very often a defensive lynchpin of a team, very few people assume from the outset that Snorlax will use Selfdestruct, so this can catch a lot of people by surprise and force them to lose an important Pokémon before they even realize what is happening. However, do note that people will be much more likely to see it coming if you happen tolead with Snorlax.
A mixed set with Fire Blast and Earthquake is standard to nail its Normal-resisting counters, then Double-Edge forces a Normal-neutral wall such as Suicune or Miltank to switch in. Selfdestruct can then OHKO that wall, typically after having also done serious damage to half of the opponent's team. Of course, there's also the option of a Curse + Selfdestruct set to bait Skarmory (at +1, STAB Selfdestruct does roughly to Skarmory what Gengar's Explosion does to Raikou), or a Selfdestruct set thatforgoesa coverage move for Lovely Kiss. As is normal for Snorlax, there's way too many options.
Snorlax is a superb defensive Exploder, too. While slow, it's OHKOed by no unboosted attack not named Explosion or Selfdestruct, and its SelfdestructOHKOesany unboosted Pokémon that does not resist it. Selfdestruct Snorlax can also stop an opposing CurseLax that’s trying to set up much more easily than other Exploders can: unboosted, it does 75-88% damage to an opposing +1 CurseLax, which is extremely difficult for that slow Snorlax to recover from even if it isn't OHKOed, and which the opposing Snorlax will almost never see coming because of how surprising Selfdestruct is. Snorlax is probably the best Exploder in the game; the main problem is that you lose out on itfunctioning as the best wall in the game once you use Selfdestruct, so it's prudent to pair it with a Pokémon such as Sleep Talk Raikou that can take over its special walling duties after it goes kamikaze.
Steelix gets access to Explosion, keeps most Normal-resistant Pokémon bar Skarmory at bay with STAB Earthquake, and can Curse up to OHKO even stubborn defensive walls with Explosion. Steelix generally fills a pivotal role as a Snorlax and Electric-immune Pokémon, so it can be hard to let go of that and allow Steelix to Explode, but as an offensive Exploder it tends to target quite a few important walls. It draws Earthquake-immune Zapdos and is also good at taking out Suicune because it can survive a single Surf and, after a single Curse, is guaranteed to OHKO it with Explosion. Steelix at +3 can do 95% minimum to +0 Def Skarmory, and at +6 it does the same to +1 Def Skarmory (important to consider if that Skarmory uses Curse). However, perhaps the biggest boon offered by Steelix's Explosion isn't by what, specifically, it targets, but rather in its allowing the user to trade downlate-game, especially against last-Pokémon CurseLax thatmight otherwise revel in being immune to Roar, or Fire Blast Snorlax that might otherwise envision getting past Steelix easily. As far as defensively Exploding, though, Steelix is too slow and is weak to too many common types of attack to save the game in many cases, although it does have the distinction of being able to survive a 999 AttackSnorlax's Earthquake.
The main role of Forretress is to set up Spikes. That's it, really. Explosion is much more secondary to Forretress's function than, say, Cloyster, because Forretress is slower and has no attacking prowess outside of a fairly weak Hidden Power Bug to dissuade Normal-resistant Pokémon from switching in. However, Forretress has the distinction of being able to use both Explosion and Rapid Spin on the same set, and it's also defensively sturdy enough to survive any hit from non-Fire Blast Snorlax, max Attack Earthquake from Marowak, and +1 Hydro Pump from Vaporeon and subsequently Explode on them to stop the sweep. Thus, Forretress's Explosion is good mostly for defensive emergencies and trading down in the endgame, and is basically useless as a wallbreaking tool.
Muk is a pretty cool, albeit unconventional, offensive Exploder. On one hand,itstruggles to really damage Rock-types and Ghost-types. On the other hand, Gengar can't do much in return, Misdreavus and Rock-types such as Tyranitar and Rhydon get put on a timer by Sludge Bomb poison, and Steel-types, the most prominent Normal-resistant Pokémon, are kept away by the threat of Fire Blast. Couple this with Muk's high Special Defense and ability to Curse up in order to take out even the sturdiest of walls with Explosion, and you have an Exploder that matches up well against plenty of threats and can Explode on pretty much anything it chooses. Generally, Exploding on a wall such as Miltank or Psychic Starmie is common, as is taking out a threatening Ground-type such as Nidoking or Marowak, or even just taking out a Zapdos that wants to beat down on it with Thunders. As a defensive cog, however, its Poison typing leaves a lot to be desired, although outspeeding Snorlax and Marowak before a Curse, in addition to handily surviving Vaporeon Surfs, makes it a pretty solid defensive Exploder (although, as with anything slower that Explodes to stop Vaporeon, watch out for Acid Armor).
Golem is another unconventional offensive Exploder that has actually been rising in popularity. The idea is that it gets Earthquake to stop most Normal-resistant Pokémon from switching into it, but it also gets Fire Blast to cover what Steelix cannot:Skarmory. From there, Golem is free to Explode on whatever non-resistant threat it chooses, although it's important to note that Golem needs to hit Suicune on the switch, unlike Steelix, and does 86% minimum with Explosion. Golem is a fairly weak defensive Exploder; although it can wall Snorlax and Curse up alongside it to ensure Explosion is able to take it out (although many times Golem would rather run Rapid Spin or Rock Slide + Fire Blast instead of Curse), outside of the Snorlax matchup Golem is too slow and too weak to Ground- and Water-type moves to be a consistent game-saver.
This is the most straightforward way to counter Explosion, and is generally the riskiest, as most good Explosion users have ways of dealing with the Normal-resistant Pokémon that could otherwise switch in. The best way to switch a Normal-resistant Pokémon into an Explosion is to do so when the risk is mitigated. For example, when the Exploder's health is low, that makes it more likely for them to pull the trigger. In addition, if you have recently set up (for example, your Snorlax has just set up Belly Drum), your opponent is likely to Explode to save the game. It also helps to have a Normal-resistant Pokémonthat matches up well against the Exploder you are trying to neutralize, such as Skarmory for Exeggutor or Gengar for Cloyster.
However, be careful switching Rock- and Steel-type Pokémon into Explosions even when it's completely predictable! Explosion still does a lot of damage even when resisted; for example, an unboosted Skarmory will take 41-48% damage from Exeggutor's Explosion. If Skarmory is looking somewhat low on health and still needs to be able to wall Snorlax, it might not be the best idea to aim to use it to absorb Exeggutor's Explosion. Even if it's safe to predict Explosion,always check damage calculations and ascertain the situation to see if you even benefit from absorbing an Explosion before you attempt to do so.
Of course, if you don't have a good Normal-resisting Pokémon in your pocket, Explosion does little good if it KOes the wrong thing. Ideally, you should be sacrificing something that doesn't stand to lose very much if your opponent actually ends up bluffing. One example would be switching Vaporeon into Cloyster, which might be looking to take out your Zapdos or Raikou with Explosion. This is safer than going to a low-health Gengar that could end up being KOed by Surf and still prevents your opponent from getting the look they want. Of course, this example assumes the common, although by no means universal, situation wherein you judge your Electric-type to be more valuable than your Vaporeon.
However, if you don't have more than one safe switch-in to your opponent's Exploder, you might want to consider using a tactic popular in RBY, whereby you take a sleeping or extremely low-health Pokémon and switch it in on the predicted Explosion. The idea is that this Pokémon was about to die anyway, so Exploding on it was effectively a waste. However, there are much fewer true "dead men walking" in GSC than in RBY, so situations wherein such a tactic is worth the risk of losing a Pokémon to an incorrect prediction are few and far between.
Using certain moves, while less common, can mitigate the effect of Explosion. For example, Raikou can use Reflect to prevent Gengar from blowing it to bits, Vaporeon can use Acid Armor to protect itself from Explosion while setting up, and Tentacruel can use Substitute to block attempts to explode on it. Also, while very uncommon, it's not completely unheard offor a DrumLax, particularly one that has been passed an Agility boost, to use Protect to foil attempts to Explode on it. Reflect is a nice way to give your whole team a reprieve from the risk of taking an offensive Explosion, thereby allowing you to more safely switch Sleep Talk users into Exeggutor, for example. Moves such as Acid Armor, Substitute, and Protect are more intended to prevent a defensive Explosion from stopping your sweep.
While this guide can act as a bit of an in-depth starting point for using and playing against Explosion, at the end of the day, there's only so much I can try to explain about Explosion with words. Ultimately, you need to just go out there, build a team with Exploders, and get a feel for when is best to Explode and when it's not, when it's best to try and call a bluff and when you should just play it safe. While somewhat reliable, Explosion is still a fairly risky move, and many "old guard" GSCers will shy away from using Explosion or trying to call bluffs because they feel they're good enough to win most games without having to take that risk. It's up to you to jump in the game and punish them for being so risk-averse.