Catching Mewtwo: The Imprison Method

I recently spent some time coming up with and then executing an overly convoluted plan for catching Raikou in Pokémon FireRed. It was a lot of fun, and I wanted to see what I could come up with next. However, I've already caught all three of the legendary birds, and to catch Entei and Suicune I can use the same method I used to catch Raikou. So what's left? Only the "final boss" (so to say) of the Kanto based games: Mewtwo.

A challenge it is! Mewtwo is one of the hardest Pokémon to catch in FireRed (depending on how you feel about the roaming legendaries), and since I don't want to use my Master Ball, I tried to figure out what I could do to make the encounter easier. To formalize things a bit, I came up with some rules reminiscent of what I did last time:

  1. Don't use a Master Ball. No exceptions!
  2. Avoid trading with a Hoenn game; that is, if possible, only use Pokémon and items obtainable in Pokémon FireRed and LeafGreen. This rule is breakable on the condition that there doesn't end up being a satisfying solution that doesn't require a Hoenn game. However, in the event that I had to break this rule, I also came up with another cute little twist to make the challenge more interesting, which I'll talk about at another time.
  3. Avoid using a Smeargle (which is only obtainable in Pokémon Emerald anyway). The reason for this is that it's often not difficult to configure a Smeargle to have whatever moveset you want, and that can make the challenge less fun. It's not a hard and fast rule, but if there's a way I can get a Pokémon other than Smeargle to know the moves I need, I'd rather do that.

I ended up coming up with 4 different strategies, of which there were two standouts. Unfortunately, all of these strategies involved trading with a Hoenn game, and one of the standouts even involved a Smeargle. I was almost resigned to breaking the Hoenn rule, but I'm happy I didn't give up, because I eventually figured out a way to modify the Smeargle method such that it no longer required Smeargle or even Hoenn! This plan is possibly (probably) even more complicated than the method I used to catch Raikou, and I had a lot of fun with it. I present to you: The Imprison Method.

Lock 'em up

The thing that annoys me the most about catching Mewtwo in FireRed/LeafGreen is the fact that it knows the move Recover, which restores up to 50% of its health. This makes it extremely hard to keep Mewtwo below 25% of its max health. Thus, the main goal I had was to somehow prevent it from being able to use Recover. It's similar to how I wanted to prevent Raikou from being able to use Roar, but this time there's no convenient Ability that disables the opponent's usage of the move. I could always use Taunt to temporarily prevent Mewtwo from using status moves, but Taunt only lasts two turns in generation III, and it'd be a better use of my time to just use Spore (which puts the target to sleep). There's also Disable, which takes the last move the target used and prevents them from using it for 4-7 turns, but this too is annoying because it's unreliable and it requires Mewtwo to use Recover again each time it expires, so that's no good either.

Instead, I made use of a move called Imprison. Imprison prevents the target from using any moves that the user knows; notably, this effect does not expire (well, unless the user switches out). This is really nice, but there aren't any Pokémon in generation III that can know both Imprison and Recover, other than Smeargle obviously, which is why the method originally required it. There is another move, though, that changes the user's moveset: Mimic. Mimic replaces itself with the last move the target used, but only until the battle ends or the user switches out. This is fine, though! The plan then becomes: wait until Mewtwo uses Recover, use Mimic to copy it, and then use Imprison to prevent Mewtwo from being able to use Recover ever again.

Mimic can be learned by almost any Pokémon in generation III, which is fortunate because Imprison can be learned by very few. There are two evolutionary lines that can learn Imprison through leveling: Vulpix, and Ralts. The latter is only obtainable in Hoenn, so it's not an option. There are also four Pokémon that can learn Imprison through breeding, but they are all in the Amorphous Egg Group, which Vulpix is not in. Vulpix it is!

You Are Getting Very Sleepy

So, I've found a way to increase Mewtwo's catch rate through keeping it at low health. Nice. However, it'd also be nice to be able to give Mewtwo a status affliction. The Cave of Dragonflies says that Mewtwo's catch rate at low health but without a status affliction is 2.106%. If I start the battle by sending in my Raichu and using Thunder Wave to paralyze Mewtwo (an affliction that won't wear off) before switching over to Ninetales, the catch rate increases to 2.833%. A low-health sleeping Mewtwo has a catch rate of 4.366%, which is a lot nicer, so while the Raichu technique would work, I'd prefer if I could find a way to put Mewtwo to sleep.

Luckily, it turns out that Vulpix can learn Hypnosis! The super fun part about this is that Vulpix only learns Hypnosis as an Egg Move, which means it's time for more breeding! Vulpix is in the Field Egg Group, and the only Pokémon in generation III in the Field Egg Group that learn Hypnosis through leveling up are Stantler and Spinda, both of which are only available in Hoenn games. Bummer. Interestingly, though, there are a number of other Pokémon in the Field Egg Group that learn Hypnosis through breeding, and two of them are also in a second group: Psyduck (which is also in the Water 1 Group) and Feebas (which is also in the Dragon Group). Feebas doesn't help me, because it's a Hoenn Pokémon, but Psyduck was worth looking into. As it turns out, the Poliwag evolutionary line is in the Water 1 Egg Group, and can learn Hypnosis through leveling up! Score!

Thus, I finally have an excuse to do some chain breeding! First, I caught a male Poliwag, which are available almost everywhere through fishing. It already knew Hypnosis when I caught it, because it learns it at level 1 and is low level enough to still know it when I catch it. Then, I caught a female Psyduck, which are also available in many locations, but notably only in FireRed. I bred them in order to get a Psyduck that knew Hypnosis, although, because I needed to pass on Hypnosis again, I needed to breed them until I got a male Psyduck. Next, I obtained a Vulpix, which you can get on the routes west and east of Saffron City, as well as in the Cinnabar Mansion, but unfortunately, only in LeafGreen. Luckily, I had a friend trade me a female Vulpix. I bred it with the Psyduck, and ended up with a Vulpix that knew Hypnosis.

Fun note: I named it "Progenitor", because it was eventually going to learn Mimic.

Built Like a Tank

Another one of the challenges in catching Mewtwo is that it can really pack a punch. It has the highest base Special Attack of any species in generation III (apart from Attack Forme Deoxys, which is event only), and to top it off, you encounter it at level 70. So, I decided that it would be really important for my Ninetales to be able to withstand a few hits from Mewtwo, and that meant maximizing its HP and Special Defense stats.

I glazed over this a little bit in my last post, but there are five factors that contribute to a Pokémon's stats:

  • Each species has a base stat for each of the six stats. These numbers are fixed for that species of Pokémon, and are why Pokémon often get stronger after evolving.
  • Each individual Pokémon has an IV (individual value), ranging from 0 to 31, for each of the six stats. These numbers range are generated when the Pokémon is created by the game, and cannot be changed.
  • When you defeat a Pokémon in battle, each Pokémon that participated in the battle or is holding an Exp. Share gains EVs (effort values). The EVs gained depend on the Pokémon that was defeated. A Pokémon can have up to 255 EVs in a single stat (of which only 252 actually count), and can have up to 510 EVs in total. EVs are how training affects a Pokémon (other than the experience gained from training). Speaking of which...
  • Level! It contributes to the stats. This is probably obvious.
  • Finally, a Pokémon's Nature contributes. There are 24 Natures. Each Pokémon is assigned one randomly, and it can't be changed. Each Nature increases one of your Pokémon's stats (other than HP) by 20%, and decreases another (that still isn't HP) by 20%.

Thus, the two factors I had under my control were EVs and level. My goal was to get 252 HP, 252 Special Defense, and 6 Speed. I started off by buying 10 HP Ups (which each give a Pokémon's 10 HP EVs) and 10 Zinc (which is the equivalent for Special Defense). Vitamins can only get a stat up to 100 EVs, though, so the next step was to EV train my Vulpix. On Route 8 (to the west of Lavender Town) is a trainer named Lass Julia who has two Clefairy, which each give 2 HP EVs. I gave Vulpix the Exp. Share and battled that trainer 38 times using the Vs. Seeker, and ended up with 252 HP EVs. Next, on Seven Island immediately south of the bridge next to the port, there is a trainer named Aroma Lady Miah who has two Bellossom, each of which award 3 Special Defense EVs. I battled them 25 times, and then fought a single Tentacool to get up to 252 Special Defense EVs. Finally, I trained briefly in Diglett's Cave to get up to 6 Speed EVs (each Diglett gives 1 Speed EV, and each Dugtrio gives 2).

After souping up my Vulpix's EVs, I switched to just trying to level it up. In the south part of Seven Island, in Sevault Canyon right above the Tanoby Ruins, there is a house with an NPC who will heal your party. There are two trainers right outside the house with high level parties. Using the Vs. Seeker, I ran around and battled these two trainers over... and over... and over again. I battled them so many times that I actually maxed out my in-game money. Vulpix learns Imprison at level 25, but in the interest of ensuring that it could hold out against Mewtwo as long as possible, I actually got it to level 100. This took a few days. But I did it anyway! Finally, I gave it a Fire Stone so that it could evolve into Ninetales, which has higher base stats than Vulpix.

Another side note: after getting my Ninetales to level 100, I calculated its IVs just out of curiosity. Most of them were fairly decent; Attack was 26, which was nice. But in a bout of irony, its HP and Special Defense IVs were both 1. Out of 31. Random numbers are cruel!

I Know You Are But What Am I

At this point, there were a few things left to prepare before I was ready for the encounter. First, I had to teach Ninetales the move Mimic. I went to the Celadon Department Store and bought a Poké Doll. Then, I went to the northwest-most house in Saffron City. On the second floor, there is an NPC who will teach one of your Pokémon the move Mimic (once) in exchange for the Poké Doll. Luckily, most Pokémon in generation III, including Ninetales, can learn Mimic this way, so I now had three fourths of the required moveset.

The final thing that Ninetales had to know was a damaging move. I realized that Ninetales now knew three moves that were learned in different ways: Hypnosis (by breeding), Imprison (by leveling up), and Mimic (by Move Tutor). So, I thought it'd be fun to teach the final move by TM. I chose to teach it Return, which is a physical move whose power is proportional to the user's friendship (maxing out at 102 power for maximum friendship). Given how much training I put Ninetales through, I knew that it had to have maximum friendship. TM27, which teaches Return, is given out by an NPC on the second floor of the gate directly to the south of Lavender Town. Part of the reason that I chose Return is because I calculated that two uses of Return should be able to get Mewtwo down to an ideal health. The other reason was because Return is essentially the opposite of Frustration, which is the damaging move that I taught my Mr. Mime when I was trying to catch Raikou.

Next, there's a hold item called Leftovers that restores 16% of the holder's health each turn. I wanted to give this to Ninetales in order to increase the amount of time it could last against Mewtwo. It can be found by standing in the exact spot that one of the two Snorlaxes were (Route 12 and Route 16) and using the Itemfinder (given to you by Professor Oak’s aide in the gate on Route 11 east of Vermillion City if you have at least 30 Pokémon in your Pokédex).

Another thing to consider is the fact that like Raikou, Mewtwo's ability is Pressure, which doubles the amount of PP your Pokémon uses. Combined with the fact that Hypnosis has 20 PP and 60% accuracy, you get on average 6 uses of the move before running out. Unfortunately, the items that you can use in battle to replenish PP are rare and limited in number. I ended up using a single Max Ether in my encounter, so it may not be a huge issue.

The Encounter

Finally, I trekked over to Cerulean Cave and encountered Mewtwo. First, I used Return in order to trick it into using Recover, and then I used Mimic to gain the move Recover. I used Imprison to prevent it from being able to use Recover again, and then used Hypnosis to put it to sleep. I then used Return twice to get it down to very low health (the first time I tried this, the Mewtwo must've had lower IVs because I accidentally fainted it, but I just soft reset the game and the second Mewtwo was reduced perfectly to a tiny amount of health). Then, I started throwing Ultra Balls at it, using Hypnosis again whenever it woke up. It frequently used Safeguard, which prevents me from putting it to sleep, and so I just had to throw Ultra Balls while it was awake while Safeguard was active, but I put it to sleep again whenever Safeguard ran out.

And then, I caught it!

My new Mewtwo and its stats.

I used 43 Ultra Balls to catch it, I used a single Max Potion, and I used a single Max Ether. Interestingly, it turned out that it was not actually Ninetales's PP that was a limiting factor; it was Mewtwo's:

Mewtwo's moves. Note how low the PP is on the non-Recover moves.

At the time I caught it, Mewtwo was five waking turns away from using Struggle and fainting itself. Fun! I'm glad that this technique worked well enough that it succeeded on the second try.

While I'm happy that I found a way to do this without using Pokémon Emerald, one problem with this technique is that it requires both FireRed (for Psyduck) and LeafGreen (for Vulpix). In my case, I had both games, plus a friend who had their own copy of LeafGreen, but someone who only had one of them would have to use a different method. There's a variant that only requires LeafGreen, wherein you forgo getting a Vulpix that knows Hypnosis and instead start the encounter with Mewtwo with a Pokémon that knows Thunder Wave, and after you paralyze Mewtwo, just switch out to Ninetales in order to carry out the rest of the technique. This leaves you with the lower catch rate of 2.833%. Additionally, there isn't a variation of this method that works with only FireRed, because Vulpix is essential.

Catching Mewtwo was the last big challenge in FireRed for me. I've got 8 Pokémon left in my Kanto Pokédex, and I've got Entei to catch in LeafGreen, which'll be the same as catching Raikou. Next, I'll be playing Pokémon Emerald, and I'm excited to come up with more unnecessary challenges for that playthrough!