Catch 'em all, right? That's the motto of the Pokémon franchise, and it's one of the simplest commands a game can ever give you. It also sounds fairly easy, as you just have to go to the right areas and chuck a few Poké Balls at different creatures to fill up your Pokédex all the way.

While it sounds easy on paper, the reality is that catching all the Pokémon is one of the most difficult and tedious things to do. Not only will certain Pokémon be exclusive to certain games, but some are much harder to find than others, let alone catch. Trying to get every creature will be an extreme test of motivation, drive, and patience.

As we've spent many years in the Pokémon world trying to catch all of the critters that live in it, we've discovered some that are notoriously difficult to obtain. While this varies from game to game, it seems that Game Freak was trying to raise a generation of blissfully masochistic children as they tried to catch Pokémon that are just about impossible to tame.

Here are our picks for 15 impossible Pokémon to catch (and how to catch them).

15 Salazzle (Sun And Moon)

When Sun and Moon first came out, there was a lot of heat floating around the Internet about the Poison and Fire raptor, Salazzle. Many people loved the creature's design and flocked to catch a Salandit so they could train and evolve it. However, most people were shocked when they finally got it to the right level, as their Salandit never evolved.

In order to get a Salazzle, you have to catch a female Salandit, which only appear a small fraction of the time (9 times out of 10, you'll get a male one). If you're lucky enough to get one, you then have to train it to level 37 in the midst of the Alola Region, full of Water and Rock types, who will crush a Salandit with ease.

14 Milotic (Ruby And Sapphire)

When Magikarp came out for Pokémon Red and Blue, it wasn't an absolute pain to level up. It was fairly common and only had to get to level 20 before evolving into a Gyarados. If only Game Freak had incorporated that same model when releasing Feebas and Milotic into Pokémon Ruby and Sapphire.

Feebas is already one of the most difficult Pokémon to catch in that game. It only appears in six water tiles in the entire map, and it's up to you to figure out what those are. If you are lucky enough to find one, you must train it fervently while raising its Beauty stat. Feebas will not evolve until its Beauty stat is completely maxed out. If that seems a bit unfair to you, we'd have to agree.

13 Regigigas (Diamond And Pearl)

One of the more interesting Legendary Pokémon introduced in Diamond and Pearl was Regigigas. Being the king of the Regi trio introduced in Gen III, many fans were excited to get their hands on this massive golem. However, once they learned how to obtain it, many people lost their excitement.

Regigigas is already programmed into the game at the Snowpoint Temple, but in order to access the room that contains him, you must first capture all three golems, Regirock, Regice, and Registeel. The catch here is that they could only be obtained in Ruby, Sapphire, and Emerald at the time, so you'd have to transfer them over. Then Regigigas himself sat at level 70, meaning you'd be battling it for a while.

12 Latios And Latias (Ruby And Sapphire)

As the Pokémon series advanced, Game Freak thought of new ways to face Legendary Pokémon. One of them was making the Pokémon roam around the entire map for the player to randomly encounter in tall grass. This was how Latios and Latias were incorporated into Ruby and Sapphire.

As you can imagine, they were a pain to catch. First, you had to track them to a spot. However, any time you switched routes or flew to that area, there was a great chance that they would move to a different place. Furthermore, when fighting them, they had the painful tendency to run away. Couple that with the fact that you're trying to be gentle with your punches, and you have one of the most aggravating sets of Pokémon to catch.

11 Shedinja (Ruby And Sapphire)

Shedinja was a weird Pokémon. When introduced, it only had one HP and an ability called Wonder Guard that prevented it from being hit unless the move was super effective. This made it an instantly desirable Pokémon for a lot of people.

Shedinja is the evolved form of Nincada, so imagine how many Nincada were being captured. However, when you finally got it to level 20, most players would instead get a Ninjask rather than a Shedinja. In order to acquire a Shedinja, you must have an open slot in your party and an extra Poké Ball in your bag. It's not the most difficult capture, but without any proper research, you'll be scratching your head for weeks trying to figure it out.

10 Drifloon (Diamond And Pearl)

Diamond and Pearl brought a lot of new Ghost types to the series, and among them was the little balloon known as Drifloon. This little cutie will be seen a few times, but if you want to catch one for yourself, you're not going to have an easy time. Drifloon doesn't appear in caves or tall grass.

In order to catch a Drifloon, first, you must beat Team Galactic while they are at the Valley Windworks. After that, Drifloon will appear, but only on Fridays. This means that if you aren't keen on resetting the internal clock of your DS, you'll be stuck waiting up to a week to get another shot at catching this balloon. Its evolution, Drifblim, is especially useful in combat.

9 Ditto (Pokémon GO)

When Pokémon GO first came out, there were many rumors of Ditto appearing in the game. While those have yet to be proven, it wasn't long before Niantic put this little blob in the game. That being said, it's not as simple as tracking a Ditto silhouette and finding its model standing next to the player character.

In order to catch a Ditto, you must find a Rattata and Pidgey. If you catch one, there is a chance that it could be a Ditto in disguise. This means that trainers of higher levels could go an extremely long time without ever catching one of these Pokémon. Furthermore, with no guarantee that a Ditto is hiding in one, people could easily go through all of their Poké Balls catching Pokémon they don't need.

8 Munchlax (Diamond And Pearl)

When Game Freak introduced the new Baby Form for Snorlax, a lot of people were enamored. Munchlax is fairly adorable, and trainers around the world were excited to finally catch one. Unfortunately, many were disappointed when they never found one in the world of Diamond and Pearl.

The truth here is that Munchlax does exist, but is very difficult to capture. Throughout the Sinnoh Region, there are trees that you can put honey on. This will attract Pokémon. One random tree in the game is selected to be able to spawn Munchlax (never revealed to you). Then, once you get to it, Muchlax only has a 1% chance of appearing. Good luck trying to add this one to your collection.

7 Zoroark (Black And White)

One of the coolest Dark type Pokémon ever created was Zoroark. This fox-like creature has the ability known as Illusion that allows it to disguise as the last Pokémon in your party. It's a powerful addition to any team and was a greatly sought after Pokémon in the Unova Region.

Fans of this Dark type would be thrown for a loop, though, as the only way to catch a Zororark was by accessing an event on HeartGold and SoulSilver. This event gave players a Shiny Raikou, Entei, or Suicune. That Pokémon then had to be transferred to Black and White, where you could then access a forest where Zoroark would be hiding. There is no other way to get Zoroark in the game.

6 Beldum (Sun And Moon)

If you find a Beldum accidentally, you're a lucky person. If you catch one on your first try, then you need to play the lottery. Beldum wasn't a difficult Pokémon to catch until Sun and Moon came out. This metallic being sits in the grass patches around the observatory. Because it has a low appearance rate, it'll be a while before you actually see one.

That's not the worst of it, though. Beldum's catch rate is nearly identical to a Legendary Pokémon, meaning you'll have to put your money where your mouth is. Better yet is the fact that Beldum only knows Take Down, which does recoil damage. If you lower its health too much, it will knock itself out. Then you're back to square one trying to find another Beldum.

5 Mew (Red And Blue)

When Pokémon Red and Blue were in development, there was one character added at the very last minute, and that character was Mew. However, because there was so little space on the Game Boy cartridge, there was no way to program a way to find Mew in the game. That being said, because its data existed, there is a method of getting it to appear.

Many people found a few glitches that exist to catch Mew, and each of them involves tricking the game into thinking that you have found a wild Mew. From there, you can catch it and add it to your team without a hitch. This glitch was kept intact for the 3DS virtual console re-releases, for those of you who want to relive the past.

4 Hitmontop (Gold And Silver)

In Gold and Silver, the Pokémon Tyrogue was introduced to the series. It is the Baby Form of Hitomchan, Hitmonlee, and Hitmontop. However, which of these it evolves into is dependent on its stats. If its attack is higher than its defense, you get a Hitmonchan. If it's the other way around, you get a Hitmonlee.

Through this method, the hardest one to obtain is Hitmontop, because you have to closely monitor Tyrogue's stats. In order for Tyrogue to evolve into Hitmontop, its attack and defense stats have to be perfectly balanced. You can imagine how difficult this is to do without a great working knowledge of the Pokémon games and how to manage stats. It takes a lot of patience.

3 Pangoro (X And Y)

There are some Pokémon who made this list because they are genuinely difficult to capture, and others who made it because nobody in their right minds would guess how to catch them the way Game Freak incorporated. Pangoro is a perfect example of the latter, as it's a huge pain if you don't know what you're doing.

Catching a Pancham is easy, but evolving it is where difficulties begin to occur. It evolves at level 32, but you must have another Dark type Pokémon in your party. While this isn't hard in the late-game, it's not so easy in the early moments of X and Y, as Dark types aren't the most common of the bunch. As long as you know what to do, obtaining a Pangoro is simple. If you don't, then good luck to you.

2 Weavile (Diamond And Pearl)

There are some Pokémon that need to be leveled up at a certain time of the day to evolve. Others need to hold a particular item. To obtain a Weavile, you have to accomplish both of these things. The first thing you need to do is catch a Sneasel (not too hard). Then it gets challenging because you have to find a Razor Claw, which isn't a common item that you can buy at a store.

From there, you need to diligently train your Sneasel so it learns all of the attacks you want it to. Then you give it the Razor Claw and level it up at night. There is no other way to obtain a Weavile. However, considering that it's extremely useful when trying to catch other Pokémon, this is a method you'll want to remember.

1 Spiritomb (Diamond And Pearl)

This is the one Pokémon in Diamond and Pearl that few people ever caught, and it's easy to see why. In the game, you'll gain an item called the Odd Keystone. From there, you have to go to Route 209 and put the Keystone in the Hallowed Tower. That's the easy part.

After you do that, you must enter the Underground (you know, that place where you find all of the fossils). You're not looking for anything in particular because you instead have to talk to 32 different people. These aren't just AI trainers either. 32 people have to be online and in the Underground in order for you to interact with them and have it count toward your Spiritomb. After you resurface, then you can fight this tormented ghost and capture it. Yeah, we didn't catch it either.