[size=5][b]A Primer On... Evolutionary Stones in Generation VIII[/b][/size]

So, it's that time again, folks! A long post on how Evolutionary Stones work - complete with examples of how a Pre-evolution's movepool turns into a Stone-Evolved Pokemon's movepool.

Please note that, due to large-scale changes from Gen VII to Gen VIII in how Level Up patterns in general function, I won't be including any Generation VII only Pokemon here.

Note also that this [b]DOES NOT APPLY TO ALL EVOLUTIONARY ITEMS[/b], which are a unique brand of their own. So items such as Chipped Pot are being actively ignored here.

[size=5][b]Types of Stone Evolution[/b][/size]

It's worth noting that not all Stone Evolutions have been cut from the same cloth! There seems to be three 'standard' cases, plus one wildcard. I'll be describing each type, and how they change from Pre- to Post-Evolution.

[b]Type A [Heart Scales][/b]
Type A Stone Evolutions is where the entire movepool is converted into Heart Scale moves - this can be seen in, for instance, Cinccino and Arcanine. This is by far the most common type. Most of this process is fairly simple, however the order of the moves is just as important as ever.[hide=Example]Let's take the Fake Pokémon [b]Omniuno[/b]. It's a Normal-Type with the following Level Up movepool:

[hide=Pre-Evolution Movepool]1: Tackle
1: Growl
5: Fake Out
10: Swift
15: Sing
20: Round
25: Swords Dance
30: Uproar
35: Recover
40: Boomburst
45: Wish
50: Hyper Beam[/hide]

Omniuno here evolves into it's evolution, [b]Omnidos[/b], as a Type A Stone Evolution. Omnidos gains [i]Perish Song[/i] as an evolutionary move, and also has [i]Metronome[/i] as a Move Relearner move. How do you think this movepool looks? It looks like... below!

[hide=Evolved Movepool]Evo: Perish Song
1: Perish Song
1: Metronome
1: Sing
1: Round
1: Swords Dance
1: Uproar
1: Recover
1: Boomburst
1: Wish
1: Hyper Beam
1: Tackle
1: Growl
1: Fake Out
1: Swift[/hide]

What's interesting is that the [b]first[/b] four moves of Omniuno have become the [b]last[/b] four of Omnidos. This might seem daft, but because of the way wild Pokemon work, it means that if you were to catch a wild Omnidos, it would have the movepool Tackle, Growl, Fake Out, and Swift![/hide]

[b]Type B [Branched Substitution][/b]
In Type B Stone Evolutions, a Pokémon that traditionally evolves into Pokemon X now has a Stone Evolution that causes it to evolve into Pokemon Y instead. This occurs only in Dawn Stone evolutions, and by definition [i]requires[/i] there to be an already existing evolutionary line, so I doubt we'll see it in CAP any time soon - however, having the notes here I'm sure might be useful one day! In these movepools, Pokemon Y's movepool essentially mirrors that of Pokemon X, however a few moves are substituted for other moves. Any move substituted out in this way is then automatically placed in Pokemon Y's Move Relearner moves. As an example, Glalie learns Crunch at Level 61. Froslass instead learns Shadow Ball at this level... so to supplement this, Froslass learns Crunch at Level 1, as a move relearner move.[hide=Example]Let's take the Fake Pokémon [b]Omniein[/b], who evolves into [b]Omnidrei[/b] at Level 32. These are both pure-Normal types! Let's look at this evolutionary line's movepool!

[hide=Omniein Movepool]1: Tackle
1: Growl
5: Fake Out
10: Swift
15: Sing
20: Round
25: Swords Dance
30: Uproar
35: Recover
40: Boomburst
45: Wish
50: Hyper Beam[/hide][hide=Omnidrei Movepool]Evo: Perish Song
1: Perish Song
1: Metronome
1: Tackle
1: Growl
1: Fake Out
1: Swift
15: Sing
20: Round
25: Swords Dance
30: Uproar
37: Recover
44: Boomburst
51: Wish
58: Hyper Beam[/hide]

However, Omniein [i]also[/i] has a branching evolution, and can also become an [b]Omnidau[/b], via a Type B stone evolution. Omnidau gains a Fire typing, and changes a few moves: Hyper Beam becomes Eruption, Uproar becomes Heat Wave, Swift becomes Ember, and Swords Dance becomes Sunny Day. Let's look at how that looks!

[hide=Omnidau Movepool]Evo: Perish Song
1: Perish Song
1: Metronome
1: Swift
1: Swords Dance
1: Uproar
1: Hyper Beam
1: Tackle
1: Growl
1: Fake Out
1: Ember
15: Sing
20: Round
25: Sunny Day
30: Heat Wave
37: Recover
44: Boomburst
51: Wish
58: Eruption[/hide]

Note how the moves that got replaced are, in order, placed into the Heart Scale moves! And, because the movepool carries on as normal, the Level 1 moves are *not* shunted to the bottom.[/hide]

[b]Type C [Evolving Substitution][/b] [size=1]Can't think of a better way to put this...[/size]
Type C is very similar to Type B, and is notable across the Eeveelution lines. The evolved Pokemon's movepool [i]looks[/i] like the pre-evolved form, however some moves have been substituted out as before. A quick example once again![hide=Example]This time we're looking at Normal-Type [b]Omnihana[/b]! [s]this movepool should be familiar by now[/s].

[hide=Omnihana Movepool]1: Tackle
1: Growl
5: Fake Out
10: Swift
15: Sing
20: Round
25: Swords Dance
30: Uproar
35: Recover
40: Boomburst
45: Wish
50: Hyper Beam[/hide]

Omnihana evolves into [b]Omnidu[/b] as a Type C Stone Evolution! Omnidu is a Normal/Ice type, and replaces a handful of moves: Swift becomes Powder Snow, Round becomes Icy Wind, Boomburst becomes Blizzard, Hyper Beam becomes Sheer Cold, and Swords Dance becomes Haze. Finally, Omnidu gains [i]Perish Song[/i] as an evolutionary move, and also has [i]Metronome[/i] as a Move Relearner move.

[hide=Omnidu Movepool]Evo: Perish Song
1: Perish Song
1: Metronome
1: Swift
1: Round
1: Swords Dance
1: Boomburst
1: Hyper Beam
1: Tackle
1: Growl
1: Fake Out
1: Powder Snow
15: Sing
20: Icy Wind
25: Haze
30: Uproar
37: Recover
44: Blizzard
51: Wish
58: Sheer Cold[/hide]

Much as with Type B, substituted moves are preserved as part of the Heart Scale set![/hide]

[b]Type D [Oddities][/b]
Type D covers 'everything else', which is all of one mon: Darmanitan-Galar. Oddly enough, this is the only [i]new[/i] Generation VIII Stone Evolution (a few others are 'new' but they've just had their Evolutionary Method changed away from location-specific ones). I'm inclined to ignore Darmanitan-Galar, as it takes it's Movepool cues primarily from being a Galarian form, so it matches with Regular Darmanitan (A Level Up evolution), rather than following any true guidelines. I've not included any examples here, as there's all of one (1) Pokémon ignoring the rules here.

[size=5][b]Stone Type Distribution[/b][/size]
Very briefly, the below is a list of Stone Evolution Pokémon, alongside their 'Type'. This might make it clear how common Type A is when compared to, well, everything else!

[b]Fire Stone[/b]
Ninetales (Type A), Arcanine (Type A), Flareon (Type C)

[b]Water Stone[/b]
Cloyster (Type A), Vaporeon (Type C), Ludicolo (Type A)

[b]Thunder Stone[/b]
Raichi (Type A), Jolteon (Type C), Vikavolt (Type C)

[b]Leaf Stone[/b]
Vileplume (Type A), Leafeon (Type C), Shiftry (Type A)

[b]Moon Stone[/b]
Clefable (Type A), Musharna (Type A)

[b]Sun Stone[/b]
Bellossom (Type A), Whimsicott (Type A), Heliolisk (Type A)

[b]Shiny Stone[/b]
Togekiss (Type A), Roserade (Type A), Cinccino (Type A)

[b]Dusk Stone[/b]
Chandelure (Type A), Aegislash (Type A)

[b]Dawn Stone[/b]
Gallade (Type B), Froslass (Type B)

[b]Ice Stone[/b]
Ninetales-Alola (Type A), Glaceon (Type C), Darmanitan-Galar (Type D)