diff --git a/src/battle-scene.ts b/src/battle-scene.ts
index 00149db3d50..3b6e716e436 100644
--- a/src/battle-scene.ts
+++ b/src/battle-scene.ts
@@ -388,6 +388,7 @@ export default class BattleScene extends SceneBase {
 
   public inputMethod: string;
   private infoToggles: InfoToggle[] = [];
+  public waveIndex: number | null;
 
   public eventManager: TimedEventManager;
 
@@ -1554,6 +1555,7 @@ export default class BattleScene extends SceneBase {
     this.resetSeed(newWaveIndex);
 
     const playerField = this.getPlayerField();
+    this.waveIndex = newWaveIndex; // temporary wave index so it can be accessed by trainer constructor
 
     if (
       this.gameMode.isFixedBattle(newWaveIndex) &&
diff --git a/src/data/trainer-config.ts b/src/data/trainer-config.ts
index 7725845e33f..5763c16217f 100644
--- a/src/data/trainer-config.ts
+++ b/src/data/trainer-config.ts
@@ -867,7 +867,7 @@ export class TrainerConfig {
      * @param isMale Whether the Gym Leader is Male or Not (for localization of the title).
      * @returns {TrainerConfig} The updated TrainerConfig instance.
      * **/
-  initForGymLeader(signatureSpecies: (Species | Species[])[], isMale: boolean, specialtyType: Type = Type.UNKNOWN, teraSlot?: number, ignoreMinTeraWave: boolean = false): TrainerConfig {
+  initForGymLeader(signatureSpecies: (Species | Species[])[], isMale: boolean, specialtyType: Type = Type.UNKNOWN, ignoreMinTeraWave: boolean = false, teraSlot?: number): TrainerConfig {
     // Check if the internationalization (i18n) system is initialized.
     if (!getIsInitialized()) {
       initI18n();
@@ -912,7 +912,9 @@ export class TrainerConfig {
     if (!ignoreMinTeraWave) {
       this.minTeraWave = GYM_LEADER_TERA_WAVE;
     }
-    this.setInstantTera(teraSlot ?? -Utils.randSeedInt(signatureSpecies.length)); // Random tera slot can be any signature species. Yes, this is the best solution for now!
+    if (!Utils.isNullOrUndefined(teraSlot)) {
+      this.setInstantTera(teraSlot);
+    }
 
     return this;
   }
@@ -968,7 +970,9 @@ export class TrainerConfig {
     this.setHasVoucher(true);
     this.setBattleBgm("battle_unova_elite");
     this.setVictoryBgm("victory_gym");
-    this.setInstantTera(teraSlot ?? Utils.randSeedInt(4, 2)); // Random tera can be any signature species
+    if (!Utils.isNullOrUndefined(teraSlot)) {
+      this.setInstantTera(teraSlot);
+    }
 
     return this;
   }
@@ -1726,14 +1730,14 @@ export const trainerConfigs: TrainerConfigs = {
   [TrainerType.PIERS]: new TrainerConfig(++t).initForGymLeader(signatureSpecies["PIERS"], true, Type.DARK).setHasDouble("piers_marnie_double").setDoubleTrainerType(TrainerType.MARNIE).setDoubleTitle("gym_leader_double").setMixedBattleBgm("battle_galar_gym"),
   [TrainerType.MARNIE]: new TrainerConfig(++t).setName("Marnie").initForGymLeader(signatureSpecies["MARNIE"], false, Type.DARK).setHasDouble("marnie_piers_double").setDoubleTrainerType(TrainerType.PIERS).setDoubleTitle("gym_leader_double").setMixedBattleBgm("battle_galar_gym"),
   [TrainerType.RAIHAN]: new TrainerConfig(++t).setName("Raihan").initForGymLeader(signatureSpecies["RAIHAN"], true, Type.DRAGON).setMixedBattleBgm("battle_galar_gym"),
-  [TrainerType.KATY]: new TrainerConfig(++t).initForGymLeader(signatureSpecies["KATY"], false, Type.BUG, -1, true).setMixedBattleBgm("battle_paldea_gym"),
-  [TrainerType.BRASSIUS]: new TrainerConfig(++t).initForGymLeader(signatureSpecies["BRASSIUS"], true, Type.GRASS, -1, true).setMixedBattleBgm("battle_paldea_gym"),
-  [TrainerType.IONO]: new TrainerConfig(++t).initForGymLeader(signatureSpecies["IONO"], false, Type.ELECTRIC, -1, true).setMixedBattleBgm("battle_paldea_gym"),
-  [TrainerType.KOFU]: new TrainerConfig(++t).initForGymLeader(signatureSpecies["KOFU"], true, Type.WATER, -1, true).setMixedBattleBgm("battle_paldea_gym"),
-  [TrainerType.LARRY]: new TrainerConfig(++t).setName("Larry").initForGymLeader(signatureSpecies["LARRY"], true, Type.NORMAL, -1, true).setMixedBattleBgm("battle_paldea_gym"),
-  [TrainerType.RYME]: new TrainerConfig(++t).initForGymLeader(signatureSpecies["RYME"], false, Type.GHOST, -1, true).setMixedBattleBgm("battle_paldea_gym"),
-  [TrainerType.TULIP]: new TrainerConfig(++t).initForGymLeader(signatureSpecies["TULIP"], false, Type.PSYCHIC, -1, true).setMixedBattleBgm("battle_paldea_gym"),
-  [TrainerType.GRUSHA]: new TrainerConfig(++t).initForGymLeader(signatureSpecies["GRUSHA"], true, Type.ICE, -1, true).setMixedBattleBgm("battle_paldea_gym"),
+  [TrainerType.KATY]: new TrainerConfig(++t).initForGymLeader(signatureSpecies["KATY"], false, Type.BUG, true, -1).setMixedBattleBgm("battle_paldea_gym"),
+  [TrainerType.BRASSIUS]: new TrainerConfig(++t).initForGymLeader(signatureSpecies["BRASSIUS"], true, Type.GRASS, true, -1).setMixedBattleBgm("battle_paldea_gym"),
+  [TrainerType.IONO]: new TrainerConfig(++t).initForGymLeader(signatureSpecies["IONO"], false, Type.ELECTRIC, true, -1).setMixedBattleBgm("battle_paldea_gym"),
+  [TrainerType.KOFU]: new TrainerConfig(++t).initForGymLeader(signatureSpecies["KOFU"], true, Type.WATER, true, -1).setMixedBattleBgm("battle_paldea_gym"),
+  [TrainerType.LARRY]: new TrainerConfig(++t).setName("Larry").initForGymLeader(signatureSpecies["LARRY"], true, Type.NORMAL, true, -1).setMixedBattleBgm("battle_paldea_gym"),
+  [TrainerType.RYME]: new TrainerConfig(++t).initForGymLeader(signatureSpecies["RYME"], false, Type.GHOST, true, -1).setMixedBattleBgm("battle_paldea_gym"),
+  [TrainerType.TULIP]: new TrainerConfig(++t).initForGymLeader(signatureSpecies["TULIP"], false, Type.PSYCHIC, true, -1).setMixedBattleBgm("battle_paldea_gym"),
+  [TrainerType.GRUSHA]: new TrainerConfig(++t).initForGymLeader(signatureSpecies["GRUSHA"], true, Type.ICE, true, -1).setMixedBattleBgm("battle_paldea_gym"),
 
   [TrainerType.LORELEI]: new TrainerConfig((t = TrainerType.LORELEI)).initForEliteFour(signatureSpecies["LORELEI"], false, Type.ICE).setBattleBgm("battle_kanto_gym").setMixedBattleBgm("battle_kanto_gym"),
   [TrainerType.BRUNO]: new TrainerConfig(++t).initForEliteFour(signatureSpecies["BRUNO"], true, Type.FIGHTING).setBattleBgm("battle_kanto_gym").setMixedBattleBgm("battle_kanto_gym"),
@@ -1748,7 +1752,7 @@ export const trainerConfigs: TrainerConfigs = {
   [TrainerType.DRAKE]: new TrainerConfig(++t).initForEliteFour(signatureSpecies["DRAKE"], true, Type.DRAGON).setMixedBattleBgm("battle_hoenn_elite"),
   [TrainerType.AARON]: new TrainerConfig(++t).initForEliteFour(signatureSpecies["AARON"], true, Type.BUG).setBattleBgm("battle_sinnoh_gym").setMixedBattleBgm("battle_sinnoh_gym"),
   [TrainerType.BERTHA]: new TrainerConfig(++t).initForEliteFour(signatureSpecies["BERTHA"], false, Type.GROUND).setBattleBgm("battle_sinnoh_gym").setMixedBattleBgm("battle_sinnoh_gym"),
-  [TrainerType.FLINT]: new TrainerConfig(++t).initForEliteFour(signatureSpecies["FLINT"], true, Type.FIRE).setBattleBgm("battle_sinnoh_gym").setMixedBattleBgm("battle_sinnoh_gym"),
+  [TrainerType.FLINT]: new TrainerConfig(++t).initForEliteFour(signatureSpecies["FLINT"], true, Type.FIRE, 3).setBattleBgm("battle_sinnoh_gym").setMixedBattleBgm("battle_sinnoh_gym"),
   [TrainerType.LUCIAN]: new TrainerConfig(++t).initForEliteFour(signatureSpecies["LUCIAN"], true, Type.PSYCHIC).setBattleBgm("battle_sinnoh_gym").setMixedBattleBgm("battle_sinnoh_gym"),
   [TrainerType.SHAUNTAL]: new TrainerConfig(++t).initForEliteFour(signatureSpecies["SHAUNTAL"], false, Type.GHOST).setMixedBattleBgm("battle_unova_elite"),
   [TrainerType.MARSHAL]: new TrainerConfig(++t).initForEliteFour(signatureSpecies["MARSHAL"], true, Type.FIGHTING).setMixedBattleBgm("battle_unova_elite"),
diff --git a/src/field/pokemon.ts b/src/field/pokemon.ts
index d7263d272a9..21dc211a776 100644
--- a/src/field/pokemon.ts
+++ b/src/field/pokemon.ts
@@ -2365,11 +2365,14 @@ export default abstract class Pokemon extends Phaser.GameObjects.Container {
       weightMultiplier += 0.4;
     }
     const baseWeights: [Moves, number][] = movePool.map(m => [ m[0], Math.ceil(Math.pow(m[1], weightMultiplier) * 100) ]);
-    const checkTera = this.getTeraType() !== Type.UNKNOWN && !this.isOfType(this.getTeraType()); // Whether the mon has an off-type Tera. If so, moves matching Tera type (and Tera Blast) are considered STAB
+    const checkTera = this.getTeraType() !== Type.UNKNOWN && !this.isOfType(this.getTeraType()); // Whether the mon has an off-type Tera. If so, moves matching Tera type (and Tera Blast) are considered STAB and boosted slightly
 
     // Trainers and bosses always force a stab move
     if (this.hasTrainer() || this.isBoss()) {
-      const stabMovePool = baseWeights.filter(m => allMoves[m[0]].category !== MoveCategory.STATUS && (this.isOfType(allMoves[m[0]].type) || (checkTera && (m[0] === Moves.TERA_BLAST || this.getTeraType() === allMoves[m[0]].type))));
+      const stabMovePool = baseWeights.filter(m => allMoves[m[0]].category !== MoveCategory.STATUS && (this.isOfType(allMoves[m[0]].type) || (checkTera && (m[0] === Moves.TERA_BLAST || this.getTeraType() === allMoves[m[0]].type)))).map(m => [
+        m[0],
+        Math.round(m[1] * ((checkTera && (m[0] === Moves.TERA_BLAST || this.getTeraType() === allMoves[m[0]].type)) ? 1.5 : 1))
+      ]);
 
       if (stabMovePool.length) {
         const totalWeight = stabMovePool.reduce((v, m) => v + m[1], 0);
@@ -4812,6 +4815,9 @@ export class EnemyPokemon extends Pokemon {
     }
 
     if (!dataSource) {
+      if (this.hasTrainer() && globalScene.currentBattle.trainer && globalScene.currentBattle.trainer.config.specialtyType > Type.UNKNOWN) {
+        this.teraType = globalScene.currentBattle.trainer.config.specialtyType;
+      }
       this.generateAndPopulateMoveset();
 
       if (shinyLock || Overrides.OPP_SHINY_OVERRIDE === false) {
@@ -4847,9 +4853,6 @@ export class EnemyPokemon extends Pokemon {
 
     this.aiType = boss || this.hasTrainer() ? AiType.SMART : AiType.SMART_RANDOM;
 
-    if (this.hasTrainer() && globalScene.currentBattle.trainer && globalScene.currentBattle.trainer.config.specialtyType > Type.UNKNOWN) {
-      this.teraType = globalScene.currentBattle.trainer.config.specialtyType;
-    }
   }
 
   initBattleInfo(): void {
diff --git a/src/field/trainer.ts b/src/field/trainer.ts
index f7f480a52d0..10991226dba 100644
--- a/src/field/trainer.ts
+++ b/src/field/trainer.ts
@@ -24,6 +24,7 @@ import i18next from "i18next";
 import { PartyMemberStrength } from "#enums/party-member-strength";
 import { Species } from "#enums/species";
 import { TrainerType } from "#enums/trainer-type";
+import { Type } from "#enums/type";
 
 export enum TrainerVariant {
     DEFAULT,
@@ -38,6 +39,7 @@ export default class Trainer extends Phaser.GameObjects.Container {
   public name: string;
   public partnerName: string;
   public originalIndexes: { [key: number]: number } = {};
+  public teraIndexes: number[] = [];
 
   constructor(trainerType: TrainerType, variant: TrainerVariant, partyTemplateIndex?: number, name?: string, partnerName?: string, trainerConfigOverride?: TrainerConfig) {
     super(globalScene, -72, 80);
@@ -68,6 +70,14 @@ export default class Trainer extends Phaser.GameObjects.Container {
       }
     }
 
+    if (this.config.trainerAI.teraMode === TeraAIMode.INSTANT_TERA && globalScene.waveIndex && globalScene.waveIndex >= this.config.minTeraWave) {
+      this.teraIndexes.push(...this.config.trainerAI.instantTeras.map(i => i < 0 ? this.getPartyTemplate().size + i : i));
+      console.log("Tera index %d", this.teraIndexes[0]);
+      if (this.teraIndexes.length === 0) {
+        this.teraIndexes.push(Utils.randSeedInt(this.getPartyTemplate().size));
+      }
+    }
+
     switch (this.variant) {
       case TrainerVariant.FEMALE:
         if (!this.config.hasGenders) {
@@ -379,6 +389,11 @@ export default class Trainer extends Phaser.GameObjects.Container {
       ret = globalScene.addEnemyPokemon(species, level, !this.isDouble() || !(index % 2) ? TrainerSlot.TRAINER : TrainerSlot.TRAINER_PARTNER);
     }, this.config.hasStaticParty ? this.config.getDerivedType() + ((index + 1) << 8) : globalScene.currentBattle.waveIndex + (this.config.getDerivedType() << 10) + (((!this.config.useSameSeedForAllMembers ? index : 0) + 1) << 8));
 
+    if (ret!.species.speciesId === Species.SHEDINJA && this.teraIndexes.includes(index) && this.config.specialtyType !== Type.BUG) {
+      this.teraIndexes.pop();
+      this.teraIndexes.push(index + 1); // If it's Shedinja and it's set to tera to something other than Bug, set tera index to the next mon
+    }
+
     return ret!; // TODO: is this bang correct?
   }
 
@@ -665,11 +680,11 @@ export default class Trainer extends Phaser.GameObjects.Container {
   }
 
   shouldTera(pokemon: EnemyPokemon): boolean {
-    if (this.config.trainerAI.teraMode === TeraAIMode.INSTANT_TERA && globalScene.currentBattle.waveIndex >= this.config.minTeraWave) {
-      if (!pokemon.isTerastallized && (this.config.trainerAI.instantTeras.includes(pokemon.initialTeamIndex) || this.config.trainerAI.instantTeras.includes(pokemon.initialTeamIndex - globalScene.getEnemyParty().length))) {
-        return true;
-      }
-    }
-    return false;
+    return (
+      this.config.trainerAI.teraMode === TeraAIMode.INSTANT_TERA
+      && globalScene.currentBattle.waveIndex >= this.config.minTeraWave
+      && !pokemon.isTerastallized
+      && this.teraIndexes.includes(pokemon.initialTeamIndex)
+    );
   }
 }