diff --git a/data/battle_scripts_1.s b/data/battle_scripts_1.s
index 11616e3002..6e667ebfe9 100644
--- a/data/battle_scripts_1.s
+++ b/data/battle_scripts_1.s
@@ -369,6 +369,7 @@ gBattleScriptsForMoveEffects:: @ 82D86A8
 	.4byte BattleScript_EffectSleepHit
 	.4byte BattleScript_EffectAttackerDefenseDownHit
 	.4byte BattleScript_EffectBodyPress
+	.4byte BattleScript_EffectExpandingForce
 
 BattleScript_EffectAttackerDefenseDownHit:
 	setmoveeffect MOVE_EFFECT_DEF_MINUS_1 | MOVE_EFFECT_AFFECTS_USER | MOVE_EFFECT_CERTAIN
@@ -2059,6 +2060,7 @@ BattleScript_EffectFusionCombo:
 BattleScript_EffectRevelationDance:
 BattleScript_EffectBelch:
 BattleScript_EffectBodyPress:
+BattleScript_EffectExpandingForce:
 
 BattleScript_HitFromAtkCanceler::
 	attackcanceler
diff --git a/include/constants/battle_move_effects.h b/include/constants/battle_move_effects.h
index 6174ca4968..cfd4ccdefa 100644
--- a/include/constants/battle_move_effects.h
+++ b/include/constants/battle_move_effects.h
@@ -353,7 +353,8 @@
 #define EFFECT_SLEEP_HIT 347 // Relic Song
 #define EFFECT_ATTACKER_DEFENSE_DOWN_HIT 348
 #define EFFECT_BODY_PRESS 349
+#define EFFECT_EXPANDING_FORCE 350
 
-#define NUM_BATTLE_MOVE_EFFECTS 350
+#define NUM_BATTLE_MOVE_EFFECTS 351
 
 #endif  // GUARD_CONSTANTS_BATTLE_MOVE_EFFECTS_H
diff --git a/src/battle_util.c b/src/battle_util.c
index 0c8f2c8d19..92662bb20f 100644
--- a/src/battle_util.c
+++ b/src/battle_util.c
@@ -7210,6 +7210,10 @@ static u16 CalcMoveBasePower(u16 move, u8 battlerAtk, u8 battlerDef)
         if (gBattleMoves[gLastUsedMove].effect == EFFECT_FUSION_COMBO && move != gLastUsedMove)
             basePower *= 2;
         break;
+    case EFFECT_EXPANDING_FORCE:
+        if (gFieldStatuses & STATUS_FIELD_PSYCHIC_TERRAIN)
+            basePower = 120;
+        break;
     }
 
     if (basePower == 0)
diff --git a/src/data/battle_moves.h b/src/data/battle_moves.h
index 69b612e0c4..b556a0a5cf 100644
--- a/src/data/battle_moves.h
+++ b/src/data/battle_moves.h
@@ -11220,7 +11220,7 @@ const struct BattleMove gBattleMoves[MOVES_COUNT] =
 
     [MOVE_EXPANDING_FORCE] =
     {
-        .effect = EFFECT_PLACEHOLDER,   //TODO
+        .effect = EFFECT_EXPANDING_FORCE,
         .power = 80,
         .type = TYPE_PSYCHIC,
         .accuracy = 100,