Massive Mass Outbreaks are the new mechanic introduced in Pokémon Legends: Arceus. There is a chance that an area will be infested with a numerous amount of Pokémon. They all have a decent chance to be shiny as well! But, you have to play it a little smart to maximize your time and save on resources required.

As far as we understand it, this is the most efficient way to hunt them for the Pokémon and Shinies you want. This guide will be updated as more information is made available.

Shiny Hunting Massive Mass Outbreaks

1. Start in Jubilife Village at the front gate
2. Check the map to see if a Massive Mass Outbreak has Spawned
3. If one has, back out of the menu to return to the village, if not enter an area and return back to Jubilife Village to start at (1) again
4. Save in Jubilife Village outside the gate (especially if there are multiple Massive Mass Outbreaks you want to check)
5. Enter the area with the Massive Mass Outbreak
6. Pay Munchlax the fee to view what Pokémon are at the Massive Mass Outbreak locations
7. Open the map and take a screenshot especially if it has something you want
8. Close the game and reopen to return to Jubilife at your save point (you can make the save point when entering the area rather than at Jubilife, but Jubilife also lets you check other Massive Mass Outbreaks if present)
9. Re-enter the area with the MMO, and the spawns should be identical to the screenshot you took
10. Get hunting the outbreaks based on your priority as there isn’t enough time to check them all

Unfortunately, you cannot return to Jubilife to “advance” the state of the game to reset the same outbreaks over and over. Each event is effectively “one-and-done,” so you have to continue checking fresh Massive Mass Outbreaks. To do this, simply enter an area and return to Jubilife Village to attempt to get a new Massive Mass Outbreak.

When it comes to hunting many of them for a shiny, follow the basic steps to get them to spawn in an area and choose your priority of ones to hit wisely. You can either catch them all or fly above them to see if the first four spawns are shiny. It’s up to you if you want to check a few or many of the inner outbreaks. However, choosing priorities allows you to maximize your chance at a rare spawn or Alpha due to the time limit.

Recommended Priority for Massive Mass Outbreaks

1. The Pokémon you are hunting
   • Rarer and more difficult Pokémon to hunt include the following:
     • Hisuian Starters
     • Unown
     • Spiritomb
     • Hisuian Forms
     • New Pokémon introduced in Hisui (such as Wyrdeer, Ursaluna, Kleavor, etc.)
     • The Pokémon that you really want a shiny Alpha of
2. The Outbreaks with a Star
   • The stars on the outbreaks indicate the outbreaks will advance. You can get evolutions, and even a chance at all Alpha spawns!
3. Anything else you need to catch or defeat to clear Pokédex Entries

Shiny Rates for Massive Mass Outbreaks

Thanks to Anubis (@Sibuna_Switch on Twitter), the shiny rates for Massive Mass Outbreaks have been determined. Check out the original link for more details, but here are the rates based on your conditions. The rates are all based on the Pokémon being in the Massive Mass Outbreak. L10 means research level 10 in the Pokédex, Perfect refers to perfect research level in the Pokédex, and SC means having the shiny charm in your possession.

L10	Perfect	SC	Shiny Rolls	Shiny Rate
			13	1/315.54
☑			14	1/293.04
☑	☑		16	1/256.05
☑		☑	17	1/241.41
☑	☑	☑	19	1/216.05

Getting Alpha Outbreaks

The outbreaks that are marked with a Star on your map will “advance” to including evolutions and possibly alpha Pokémon as you clear them out. So, to get Alpha shinies from these outbreaks, go after the outbreaks that are marked with stars on your map. Once the mechanics are fully understood, the chances for getting an Alpha outbreak will be updated here.

You can hunt these Alpha Outbreaks individually if you wish to improve your chances. See the next section.

Advanced Hunting for Single and Alpha Hordes

If you stumble upon a rare horde that produces a second wave of spawns (i.e. it says “A new horde is forming” after clearing the initial outbreak), you can do some resetting and fancy combination of events to check more of the spawns. This takes advantage of what is known as “multi-despawn” or “multi-KO”, where the game will produce different Pokémon depending on if it has to generate more than one Pokémon at a time to fill the empty slots. So, here’s the method:

1. Go to an outbreak that you’re interested in and save just a little way from it
2. Catch each Pokémon one at a time until the outbreak is complete
3. If the outbreak continues, you’ll get 4 spawns of the next outbreak
4. Catch three of the Pokémon in the continued outbreak to replace their spawns
5. You’ll have now seen the six or seven Pokémon in the new outbreak, and you can reset the game if there was no shiny
6. Go back to step (2) but now follow the following table to produce new spawns

Here’s a table with just a few possible permutations to get unique second wave spawns:

	Spawn Number
Reset #	1	2	3	4	5	6	7	8	9	10
0	C	C	C	C	C	C	C	C	C	C
1	KO	KO	C	C	C	C	C	C	C	C
2	KO	KO	KO	C	C	C	C	C	C	C
3	KO	KO	KO	KO	C	C	C	C	C	C
4	KO	KO	KO	KO	C	C	C	C	C	C
5	KO	KO	KO	KO	KO	C	C	C	C	C
6	KO	KO	KO	KO	KO	KO	C	C	C	C
7	KO	KO	KO	KO	KO	C	C	C	C	C
8	KO	KO	KO	KO	KO	KO	C	C	C	C
9	KO	KO	KO	KO	KO	KO	KO	C	C	C
10	KO	KO	KO	KO	KO	KO	C	C	C	C
11	KO	KO	KO	KO	KO	KO	KO	C	C	C
12	KO	KO	KO	KO	KO	KO	KO	KO	C	C
13	KO	KO	KO	KO	KO	KO	C	C	C	C
14	KO	KO	KO	KO	KO	KO	KO	C	C	C
15	KO	KO	KO	KO	KO	KO	KO	KO	C	C
16	KO	KO	KO	KO	KO	KO	KO	C	C	C

KEY: C is “catch”, KO is “Knock Out.” The colors indicate what to do first, meaning, on row #1, you would KO two at the same time, then catch the rest. But on row #11, you would KO four at the same time then KO three. This extends to the whole table for all different color combinations. If you want to see all possible combinations of events to get unique spawns, check out our tracker tool for the Massive Mass Outbreaks!

Also note that the first outbreak is limited to between eight and ten spawns, so if a row on the table exceeds the eight spawn mark and your outbreak only has eight, then that row is not possible. There are also possiblities for catching in between the KO’s, but that extends the table dramatically.

There are a significant number of possiblities for getting unique spawns., we have a tracker tool for the Massive Mass Outbreaks! It will save your progress and show you all possible combinations.

Several YouTubers have outlined this method, but having a static table on a website is more convenient. Thanks to Austin John Plays and the other Pokémon fans for testing this method out.

The advanced methods can also be extended to Ghost Spawns. See the next section of this page for information on that.

Ghost Spawn Information

It turns out another method to extend unique spawns has been discovered when there are still Pokémon remaining in an outbreak but no more can spawn in (such as only three remaining of the original eight spawns). If you travel so that the Pokémon are completely out of sight (you can place down a marker on your map and travel away until the marker is about 120 away or fast travel to camp or another close landmark) and return to the outbreak, you will get different results in the second wave.

What happens is that when you leave the area, the game attempts to “fill in” the missing spawns. The RNG advances to try and create the Pokémon, but they’re never “fully” created because there’s no more room for them because the number of spawns has been exhausted. The RNG is still advanced forward, so what happens to the second wave of spawns is completely different.

This is one of the reasons why people lose shinies in the final wave. If you leave the outbreak with fewer than four remaining Pokémon on the field from the first wave you will have different second wave results. Be extremely careful when traveling to camp or leaving the area to avoid aggression especially if you are repeating past actions to get a shiny again.

Again, this guide will be updated as more information is made available!