Updated 20/12/2021 for toxic behaviour
It might be best if somebody adds this to their leveling guide to avoid clutter, so I'm putting this in WIP for now.
I've been using this method for over a year, but even after so long it doesn't seem as though the method is well-publicized. So, I decided to make a short guide myself.
Video: https://www.youtube.com/watch?v=BuijK_ZA1mw
tl;dr: Leech Seed, Leech Seed, Leech Seed, Toxic, Toxic, Memento, swap to your low-level pokemon.
Memento method
All you need: Jumpluff or Whimsicott. You can probably also use Lilligant and Cherrim if you teach them Healing Wish rather than Memento.
- Toxic
- Leech Seed
- Memento/Healing Wish
Execution is simple, just note that you can't use any damaging skills if you want the HP to be accurate, so spam Leech Seed or a non-damaging move (e.g. synthesis) until turn 4;
Turn 1: Leech Seed deals 2/16 HP. (14/16 remaining)
Turn 2: Leech Seed deals 2/16 HP. (12/16 remaining)
Turn 3: Leech Seed deals 2/16 HP. (10/16 remaining)
Turn 4: Toxic deals 1/16 HP. (9/16 remaining)
Leech Seed deals 2/16 HP. (7/16 remaining)
Turn 5: Toxic deals 2/16 HP. (5/16 remaining)
Leech Seed deals 2/16 HP. (3/16 remaining)
Turn 6: Memento faints your Jumpluff.
Toxic deals 3/16 HP. (0/16 remaining)
At this point, the enemy pokemon will usually have <15 HP remaining because most pokemon won't have HP divisible by 16.
Switch in your low-level pokemon.
Leech Seed will immediately take the remaining HP, fainting the enemy pokemon before it has a chance to attack.
This works because the game currently recognizes the switch following Memento as part of the 'same turn' that Memento was used, instead of starting a new turn.
Advantages:
- Doesn't involve focus sash, false swipe, or sturdy.
- Importantly, doesn't rely on priority moves, making it much easier to train many low-level pokemon. Depending on your EXP buffs and your luck with encounters, it takes less than an hour to get Magikarp from 5 to 95.
Disadvantages:
- Doesn't work against poison or grass-types, since they'll be immune to Toxic/Leech Seed.
- Jumpluff has poor defensive typing/defensive stats and takes a lot of damage from rock/flying/poison, making Cerulean Cave land difficult when compared to water. Lilligant/Cherrim/Whimsicott won't have problems with rock, but Jumpluff is way more accessible to most players.
- Your Jumpluff are going to hate you.