Charge move replacement glitch
The charge move replacement glitch is a natural glitch, and recurring glitch which occurs in Generations V, VI, VII and VIII of the core Pokémon games.
In a Double or Triple Battle, if a Pokémon hasn't yet moved in a turn, but levels up from experience gained mid-battle and learns a new move to replace the same move it had clicked that turn, since Generation V, the selected move will still be used even though the Pokémon no longer knows it. (In Generation III-IV, the new move that's currently in that slot will be used instead.)
If the old move that gets overwritten this way is a move with a charge turn, such as Dig or Solar Beam, the move's charging turn will be executed as usual, but the second turn behaves strangely. Instead of completing the charged move, the Pokémon will use whatever its most recently used move was prior to the charge turn, without consuming PP, and targeting the same slot it was targeting on that previous instance of the move. In any case, if the original charge move was one that came with a semi-invulnerable turn, the second turn will bring the Pokémon back to standard vulnerability, and if the move was Sky Drop, the same applies to the Pokémon that was picked up.
If there is no such prior move in the Pokémon's active stint, perhaps by triggering this glitch on the first turn of a battle, then instead of having a text box appear that says "<Pokémon> used <Move>!" the text box will simply say "!" indicating an attempt to use the null move with index number 0; the move will automatically target the player's leftmost slot, and will fail if the move user itself is in that slot. In Generation VIII, the null move's data is a copy of move #1, Pound (a 40-power, Normal-type physical attack). In earlier generations, it is a status move with 0% accuracy, and will always miss unless one of the Pokémon has No Guard. If that ability forces the move to hit, it will be treated as a 0-power move, which usually results in exactly 1 damage regardless of stats, except that Ghost types are immune. This damage will not trigger either Kee Berry or Maranga Berry, nor is it eligible to be countered back by any of Counter, Mirror Coat, or Metal Burst (despite the last of these normally being agnostic about the damage category). In a Triple Battle, if the user is in the right-side slot, its teammate in the left-side slot will avoid the null move even if No Guard is used, because it's out of range and the null move does not have the cross-field targeting flag set.
If the move that's repeated this way in place of the charge move's second turn is...
- a move that's no longer in the Pokémon's current moveset, a move with no PP left, or a move that would normally be prevented by Assault Vest:
- The move can still be used successfully.
- a move that's subject to the effects of Disable, Heal Block, Gravity, Throat Chop, Taunt, or Imprison:
- The move is prevented, with the text box displaying the standard notice for whichever applicable effect stopped it. In the case of the null move, this method can be used to convince the game to display its formal name from the move data table (prior to Generation VIII): "<Pokémon> can't use --- after the taunt!" If the charge move that gets replaced is Geomancy, but the repeated move is not a status move, Taunt will not prevent it.
- a move with altered priority:
- The move will fire off at whatever priority the replacement move normally has. For example, a charge move that gets replaced with a repeated Quick Attack will use +1 priority; one that gets replaced with Roar will use -6.
- a move with a charge turn, perhaps the same one that was just overwritten:
- The replacement move will be the second turn of the charge move firing off immediately, without having to spend a second charging turn beforehand.
- a move with a recharge turn (Hyper Beam, Blast Burn):
- The move will be used, and if it hits, the Pokémon will have to spend a turn recharging as usual.
- a multi-turn rampage move (Thrash, Rollout):
- The move will be used, and if it hits, the Pokémon will become locked into it for its entire standard duration.
- a move that calls another move (Metronome, Assist):
- The move that gets repeated is the original container move, not the move that it called. This means that it can re-evaluate a different move to be called from the repeat performance.
- Mimic or Sketch:
- These moves have an intrinsic check to make sure that they're in the Pokémon's current moveset, otherwise they will fail. Hence, if the original instance of one of these moves succeeded, the repeated version will always fail (unless the Pokémon using this glitch is Smeargle, and it levels up to learn a new instance of Sketch). On the flip side, if the original instance failed, the reprise is eligible to succeed; a move that's learned this way will go into the move slot of Mimic or Sketch, not the slot of the charge move that was selected and overwritten.
- Like Mimic and Sketch, a repeated Transform can only possibly succeed if the initial use failed. In fact, if the initial Transform succeeds, the Pokémon is not subject to this glitch at all: any changes to its moves from leveling up are kept separate from its transformed moveset, and instead of repeating Transform, the charge move will complete its second turn as usual.
- Focus Punch, Beak Blast, or Shell Trap:
- These moves will produce their usual notice at the beginning of the turn and are subject to their standard mechanics, such as a Focus Punch user losing their focus if they get hit earlier in the same turn and being unable to execute the move.
- Stomping Tantrum:
- The unfinished charge move is not considered a failure, and Stomping Tantrum will not get increased power, even if Stomping Tantrum itself failed the previous time it was used.
- Destiny Bond:
- Despite the intervening charge turn, the repeated move is considered stale, thus (in Generation VII forward, in which Destiny Bond is subject to a staleness rule) the repeat performance will fail if the previous use succeeded, and vice versa.
- a protection move (Protect, Spiky Shield):
- Unlike Destiny Bond, repeating one of these moves after the intervening charge turn does not cause it to be considered stale, and it will not have a chance to fail. Repeating Mat Block will fail, of course, but not because of a staleness rule.
- a generic Z-move (Breakneck Blitz, Bloom Doom):
- Instead of the "<Pokémon> used <Move>!" text box, the text box that appears will be completely blank, without even the exclamation point that the null move provides. The Pokémon then uses a version of the Z-move that has only 1 power. If animations are on, the target's health bar will not appear to change at all, but the damage has been dealt and will be taken into account the next time it takes damage or restores HP. This result is consistent with what happens when one of these Z-moves is placed directly into a normal moveslot via hacking, and used that way. Even if the prior Z-move was a special move, the 1-power move will be physical.
- a signature Z-move (Catastropika, Malicious Moonsault):
- The blank text box will appear as in the above case, but the move will be used with its full standard power.
- a status Z-move, other than Extreme Evoboost:
- The non-Z version of the move will be used. The Pokémon will not receive any additional bonuses from Z-power.