Partially implemented mimicry. Edge cases where

other effects also change type may exhibit some
unintended behavior (soak, forest's curse).

Streamlined on summon weather/terrain effects.

src/data/ability.ts

@@ -2126,6 +2126,32 @@ export class PostTerrainChangeAddBattlerTagAttr extends PostTerrainChangeAbAttr
   }
 }
 
+export class PostTerrainChangeTypeAttr extends PostTerrainChangeAbAttr {
+  private oldType: Type[];
+  private terrainToTypeMap: Record<TerrainType, Type>;
+
+  constructor(terrainToTypeMap: Record<TerrainType, Type>) {
+    super();
+    this.terrainToTypeMap = terrainToTypeMap;
+  }
+
+  applyPostTerrainChange(pokemon: Pokemon, passive: boolean, terrain: TerrainType, args: any[]): boolean {
+
+    if (this.terrainToTypeMap[terrain] == Type.UNKNOWN) {
+      if (pokemon.summonData.types == null) return false;
+      pokemon.summonData.types = null;
+      pokemon.updateInfo();
+      pokemon.scene.queueMessage(getPokemonMessage(pokemon, ` transformed\nback into its original type!`));
+      return true;
+    }
+
+    pokemon.summonData.types = [this.terrainToTypeMap[terrain]]
+    pokemon.updateInfo();
+    pokemon.scene.queueMessage(getPokemonMessage(pokemon, ` transformed\ninto the ${Utils.toReadableString(Type[pokemon.getTypes()[0]])} type!`));
+    return true;
+  }
+}
+
 function getTerrainCondition(...terrainTypes: TerrainType[]): AbAttrCondition {
   return (pokemon: Pokemon) => {
     const terrainType = pokemon.scene.arena.terrain?.terrainType;
@@ -3637,7 +3663,11 @@ export function initAbilities() {
     new Ability(Abilities.POWER_SPOT, 8)
       .unimplemented(),
     new Ability(Abilities.MIMICRY, 8)
-      .unimplemented(),
+      .attr(PostTerrainChangeTypeAttr, {
+        [TerrainType.NONE]: Type.UNKNOWN, [TerrainType.MISTY]: Type.FAIRY, [TerrainType.ELECTRIC]: Type.ELECTRIC,
+        [TerrainType.GRASSY]: Type.GRASS, [TerrainType.PSYCHIC]: Type.PSYCHIC
+      })
+    .partial(),
     new Ability(Abilities.SCREEN_CLEANER, 8)
       .unimplemented(),
     new Ability(Abilities.STEELY_SPIRIT, 8)
@@ -3740,14 +3770,12 @@ export function initAbilities() {
     new Ability(Abilities.ELECTROMORPHOSIS, 9)
       .attr(PostDefendApplyBattlerTagAbAttr, (target, user, move) => move.category !== MoveCategory.STATUS, BattlerTagType.CHARGED),
     new Ability(Abilities.PROTOSYNTHESIS, 9)
-      .conditionalAttr(getWeatherCondition(WeatherType.SUNNY, WeatherType.HARSH_SUN), PostSummonAddBattlerTagAbAttr, BattlerTagType.PROTOSYNTHESIS, 0, true)
       .attr(PostWeatherChangeAddBattlerTagAttr, BattlerTagType.PROTOSYNTHESIS, 0, WeatherType.SUNNY, WeatherType.HARSH_SUN)
       .attr(UncopiableAbilityAbAttr)
       .attr(UnswappableAbilityAbAttr)
       .attr(NoTransformAbilityAbAttr)
       .partial(), // While setting the tag, the getbattlestat should ignore all modifiers to stats except stat stages
     new Ability(Abilities.QUARK_DRIVE, 9)
-      .conditionalAttr(getTerrainCondition(TerrainType.ELECTRIC), PostSummonAddBattlerTagAbAttr, BattlerTagType.QUARK_DRIVE, 0, true)
       .attr(PostTerrainChangeAddBattlerTagAttr, BattlerTagType.QUARK_DRIVE, 0, TerrainType.ELECTRIC)
       .attr(UncopiableAbilityAbAttr)
       .attr(UnswappableAbilityAbAttr)

src/field/arena.ts

@@ -343,6 +343,10 @@ export class Arena {
     return this.terrain?.terrainType || TerrainType.NONE;
   }
 
+  getWeatherType(): WeatherType {
+    return this.weather?.weatherType || WeatherType.NONE;
+  }
+
   getAttackTypeMultiplier(attackType: Type, grounded: boolean): number {
     let weatherMultiplier = 1;
     if (this.weather && !this.weather.isEffectSuppressed(this.scene))

src/phases.ts

@@ -30,7 +30,7 @@ import { Weather, WeatherType, getRandomWeatherType, getTerrainBlockMessage, get
 import { TempBattleStat } from "./data/temp-battle-stat";
 import { ArenaTagSide, ArenaTrapTag, MistTag, TrickRoomTag } from "./data/arena-tag";
 import { ArenaTagType } from "./data/enums/arena-tag-type";
-import { CheckTrappedAbAttr, IgnoreOpponentStatChangesAbAttr, PostAttackAbAttr, PostBattleAbAttr, PostDefendAbAttr, PostSummonAbAttr, PostTurnAbAttr, PostWeatherLapseAbAttr, PreSwitchOutAbAttr, PreWeatherDamageAbAttr, ProtectStatAbAttr, RedirectMoveAbAttr, BlockRedirectAbAttr, RunSuccessAbAttr, StatChangeMultiplierAbAttr, SuppressWeatherEffectAbAttr, SyncEncounterNatureAbAttr, applyAbAttrs, applyCheckTrappedAbAttrs, applyPostAttackAbAttrs, applyPostBattleAbAttrs, applyPostDefendAbAttrs, applyPostSummonAbAttrs, applyPostTurnAbAttrs, applyPostWeatherLapseAbAttrs, applyPreStatChangeAbAttrs, applyPreSwitchOutAbAttrs, applyPreWeatherEffectAbAttrs, BattleStatMultiplierAbAttr, applyBattleStatMultiplierAbAttrs, IncrementMovePriorityAbAttr, applyPostVictoryAbAttrs, PostVictoryAbAttr, applyPostBattleInitAbAttrs, PostBattleInitAbAttr, BlockNonDirectDamageAbAttr as BlockNonDirectDamageAbAttr, applyPostKnockOutAbAttrs, PostKnockOutAbAttr, PostBiomeChangeAbAttr, applyPostFaintAbAttrs, PostFaintAbAttr, IncreasePpAbAttr, PostStatChangeAbAttr, applyPostStatChangeAbAttrs, AlwaysHitAbAttr, PreventBerryUseAbAttr, StatChangeCopyAbAttr } from "./data/ability";
+import { CheckTrappedAbAttr, IgnoreOpponentStatChangesAbAttr, PostAttackAbAttr, PostBattleAbAttr, PostDefendAbAttr, PostSummonAbAttr, PostTurnAbAttr, PostWeatherLapseAbAttr, PreSwitchOutAbAttr, PreWeatherDamageAbAttr, ProtectStatAbAttr, RedirectMoveAbAttr, BlockRedirectAbAttr, RunSuccessAbAttr, StatChangeMultiplierAbAttr, SuppressWeatherEffectAbAttr, SyncEncounterNatureAbAttr, applyAbAttrs, applyCheckTrappedAbAttrs, applyPostAttackAbAttrs, applyPostBattleAbAttrs, applyPostDefendAbAttrs, applyPostSummonAbAttrs, applyPostTurnAbAttrs, applyPostWeatherLapseAbAttrs, applyPreStatChangeAbAttrs, applyPreSwitchOutAbAttrs, applyPreWeatherEffectAbAttrs, BattleStatMultiplierAbAttr, applyBattleStatMultiplierAbAttrs, IncrementMovePriorityAbAttr, applyPostVictoryAbAttrs, PostVictoryAbAttr, applyPostBattleInitAbAttrs, PostBattleInitAbAttr, BlockNonDirectDamageAbAttr as BlockNonDirectDamageAbAttr, applyPostKnockOutAbAttrs, PostKnockOutAbAttr, PostBiomeChangeAbAttr, applyPostFaintAbAttrs, PostFaintAbAttr, IncreasePpAbAttr, PostStatChangeAbAttr, applyPostStatChangeAbAttrs, AlwaysHitAbAttr, PreventBerryUseAbAttr, StatChangeCopyAbAttr, PostTerrainChangeAbAttr, applyPostTerrainChangeAbAttrs, applyPostWeatherChangeAbAttrs, PostWeatherChangeAbAttr } from "./data/ability";
 import { Unlockables, getUnlockableName } from "./system/unlockables";
 import { getBiomeKey } from "./field/arena";
 import { BattleType, BattlerIndex, TurnCommand } from "./battle";
@@ -1043,6 +1043,9 @@ export class PostSummonPhase extends PokemonPhase {
     const pokemon = this.getPokemon();
 
     this.scene.arena.applyTags(ArenaTrapTag, pokemon);
+
+    applyPostWeatherChangeAbAttrs(PostWeatherChangeAbAttr, pokemon, this.scene.arena.getWeatherType());
+    applyPostTerrainChangeAbAttrs(PostTerrainChangeAbAttr, pokemon, this.scene.arena.getTerrainType());
     applyPostSummonAbAttrs(PostSummonAbAttr, pokemon).then(() => this.end());
   }
 }