Evolution has been a core part of the Pokemon franchise from the beginning, allowing the series' central critters to grow into more powerful forms as they spend time in your party. Over the years, a variety of methods for evolving Pokemon have been introduced to keep things fresh, with some methods more bizarre than others.
Some Pokemon, though, are given a special evolution method only for it later to be changed. Though such cases are rare, they do happen, and these alterations are strange and interesting aspects of Pokemon history. Here are ten Pokemon who were assigned one evolution method, but later had it changed to something else.
10 Goodra - Weather Conditions Reduced
Sliggoo evolves into Goodra when levelled up while it's raining in the overworld, starting from level 50. This wasn't always the case, as in the Gen VII games, Goodra evolves if the overworld is foggy, too. In Generation VIII, though, this doesn't work, and it has to be raining.
The reason for this change is likely due to the fact that in Sword & Shield, fog changed a bit. The Galar games had plenty of weather conditions, and fog was one of them, but its presence in the overworld now means battles occur on Misty Terrain. The weather type's new association with the Fairy-type could have caused confusion if connected to non-Fairy Goodra, which might explain the change.
9 Leafeon - No More Moss Rock
From its introduction in Generation IV through to Generation VII, Leafeon was evolved by levelling up Eevee in the vicinity of a Moss Rock found somewhere within a region (typically a forest). Seeking these rocks out was a fun challenge, and continued the fun trend of each batch of Eeveelutions getting a new evolution method.
In Generation VIII's Sword & Shield, though, Leafeon's evolution method was changed. Galar has no Moss Rock, and instead, Leafeon evolves using the Leaf Stone — a bit of a shame, considering how fun the old method was.
8 Magnezone - Magnetic Fields Replaced
Magneton and Nosepass were given new evolutions in Sinnoh — Magnezone and Probopass. These cool new evolutions could only be obtained by levelling up in the presence of a special magnetic field, such as the one in Mt. Coronet. These fields showed up in subsequent regions, allowing the evolutions to remain obtainable.
Sword & Shield marked the turning point for this evolution method too. While the Nosepass line was one of the ones that didn't even make it into the game, Magneton did, and since Galar had no special magnetic field, it instead evolved into Magnezone by being exposed to a Thunder Stone.
7 Milotic - Beauty Stat > Held Item
Obtaining Feebas is infamously difficult, and so too was evolving it — at least back when it was introduced in Generation III. You had to raise its Beauty stat by tediously farming berries to make Pokeblocks, and only once the stat was high enough could it become Milotic.
In Generation V, however, both obtaining and evolving Feebas were made easier. Milotic could now be obtained simply by trading a Feebas holding a Prism Scale — a far more convenient way of acquiring the powerful Water-type.
6 Any Pokemon With a Time of Day Evolution Requirement
In Gold & Silver, a night/day cycle was introduced, and it brought with it time-dependent evolutions. Umbreon and Espeon, for example, could only be obtained by levelling up an Eevee with high Friendship during the night or day, respectively.
While this cycle has remained a part of almost every subsequent Pokemon game, there are a few exceptions. Night/day evolutions were simply unobtainable in FireRed in LeafGreen, but Pokemon XD: Gale of Darkness came up with an alternate solution — night-evolving Pokemon instead used the Moon Shard, and day-evolving ones used the Sun Shard.
5 Glaceon - The Second Rock Removal
The other half of the Sinnoh Eeveelutions, Glaceon needed a special rock to evolve, like its counterpart Leafeon. For Glaceon, the Ice Rock was required, and having to track it down to obtain your Ice-type Eeveelution made Glaceon feel that bit more special.
As with Leafeon, Galar changed this, and Glaceon evolves with the Ice Stone instead. This means five out of the eight Eeveelutions (at time of writing) evolve with stones — a far cry from the exciting variety of evolution methods they originally had.
4 Vikavolt - Another Casualty of Magnetic Field Removal
For many Generations, Probopass and Magnezone were the only ones to evolve using magnetic fields. But this all changed in Sun & Moon, as Charjabug could turn evolve Vikavolt when levelled up in the presence of such a field.
As we know, however, Alola would be the last region to contain such a field, and like Magneton, Charjabug's evolution was changed to require exposure to a Thunder Stone. Though Generation VIII introduced many unique evolution methods of its own, it's a shame it removed so many fun older ones.
3 Lycanroc - No More Game Exclusivity
Lycanroc was introduced in Sun & Moon, though maybe that should be Sun or Moon, as, of Lycanroc's three forms, one was only obtainable in Sun (Midday form), and another in Moon (Midnight form). The third (Dusk form) required a special Rockruff.
In Sword & Shield, this exclusivity was removed and Lycanroc's evolutions became simple time-of-day ones. The reason for this could be that "Sword" and "Shield" lack the connections to midday and midnight that "Sun" and "Moon" do, but contrary to many of the more controversial changes in Gen VIII, wider availability is always a good thing.
2 Sylveon - From Affection to Friendship
Sylveon was a poster Pokemon for many of Generation VI's new mechanics. It bore the new Fairy-type, and had two requirements to evolve from Eevee: the Eevee had to know a Fairy-type move, and it had to have at least two levels of Affection, obtained in the new Pokemon Amie.
This Affection requirement carried over into Sun & Moon, where Affection was built up in Pokemon Refresh, but in Sword and Shield, it was changed to simple Friendship. The Fairy-type move requirement was kept at least, so there was no danger of accidentally getting an Espeon or Umbreon.
1 Shedinja - An Added Poke Ball
In Generation 3, when Shedinja was introduced, its evolution worked as follows: level up Nincada to level 20, and make sure you have an extra space in your party. The Nincada evolves into Ninjask, and the empty space in the party is filled by its discarded cicada shell, Shedinja.
In Generation IV, a slight tweak was made to this method, presumably for balance reasons. In addition to the extra party slot, players now needed to ensure they also had a spare Poke Ball in their bag, which would be consumed upon Shedinja's arrival. To get a Pokemon, you need a Poke Ball, and Shedinja is no exception.