diff --git a/asm/macros/battle_script.inc b/asm/macros/battle_script.inc
index debac5acb7..59d98a6c1d 100644
--- a/asm/macros/battle_script.inc
+++ b/asm/macros/battle_script.inc
@@ -1444,6 +1444,11 @@
 	various \battler, VARIOUS_INVERT_STAT_STAGES
 	.endm
 	
+	.macro setterrain ptr
+	various BS_ATTACKER, VARIOUS_SET_TERRAIN
+	.4byte \ptr
+	.endm
+	
 @ helpful macros
 	.macro setstatchanger stat, stages, down
 	setbyte sSTATCHANGER \stat | \stages << 4 | \down << 7
diff --git a/data/battle_scripts_1.s b/data/battle_scripts_1.s
index e8a6f2ad3a..e880bf88bc 100644
--- a/data/battle_scripts_1.s
+++ b/data/battle_scripts_1.s
@@ -282,6 +282,24 @@ gBattleScriptsForMoveEffects:: @ 82D86A8
 	.4byte BattleScript_EffectIonDeluge
 	.4byte BattleScript_EffectFreezeDry
 	.4byte BattleScript_EffectTopsyTurvy
+	.4byte BattleScript_EffectMistyTerrain
+	.4byte BattleScript_EffectGrassyTerrain
+	.4byte BattleScript_EffectElectricTerrain
+	.4byte BattleScript_EffectPsychicTerrain
+	
+BattleScript_EffectMistyTerrain:
+BattleScript_EffectGrassyTerrain:
+BattleScript_EffectElectricTerrain:
+BattleScript_EffectPsychicTerrain:
+	attackcanceler
+	attackstring
+	ppreduce
+	setterrain BattleScript_ButItFailed
+	attackanimation
+	waitanimation
+	printfromtable gTerrainStringIds
+	waitmessage 0x40
+	goto BattleScript_MoveEnd
 	
 BattleScript_EffectTopsyTurvy:
 	attackcanceler
diff --git a/include/constants/battle_move_effects.h b/include/constants/battle_move_effects.h
index ab05359933..4fb18611a1 100644
--- a/include/constants/battle_move_effects.h
+++ b/include/constants/battle_move_effects.h
@@ -246,7 +246,7 @@
 #define EFFECT_TAILWIND 240
 #define EFFECT_EMBARGO 241
 #define EFFECT_AQUA_RING 242
-#define EFFECT_TRICK_TOOM 243
+#define EFFECT_TRICK_ROOM 243
 #define EFFECT_WONDER_ROOM 244
 #define EFFECT_MAGIC_ROOM 245
 #define EFFECT_MAGNET_RISE 246
@@ -271,5 +271,9 @@
 #define EFFECT_ION_DELUGE 265
 #define EFFECT_FREEZE_DRY 266
 #define EFFECT_TOPSY_TURVY 267
+#define EFFECT_MISTY_TERRAIN 268
+#define EFFECT_GRASSY_TERRAIN 269
+#define EFFECT_ELECTRIC_TERRAIN 270
+#define EFFECT_PSYCHIC_TERRAIN 271
 
 #endif  // GUARD_CONSTANTS_BATTLE_MOVE_EFFECTS_H
diff --git a/include/constants/battle_script_commands.h b/include/constants/battle_script_commands.h
index 0156f967b0..d301a76605 100644
--- a/include/constants/battle_script_commands.h
+++ b/include/constants/battle_script_commands.h
@@ -91,6 +91,7 @@
 #define VARIOUS_TRY_HEAL_PULSE                  42
 #define VARIOUS_TRY_QUASH                       43
 #define VARIOUS_INVERT_STAT_STAGES              44
+#define VARIOUS_SET_TERRAIN                     45
 
 // atk80, dmg manipulation
 #define ATK80_DMG_CHANGE_SIGN                               0
diff --git a/include/constants/battle_string_ids.h b/include/constants/battle_string_ids.h
index 2745146477..3d78389816 100644
--- a/include/constants/battle_string_ids.h
+++ b/include/constants/battle_string_ids.h
@@ -497,6 +497,10 @@
 #define	STRINGID_PKMNBLEWAWAYSTEALTHROCK 494
 #define	STRINGID_IONDELUGEON 495
 #define	STRINGID_TOPSYTURVYSWITCHEDSTATS 496
+#define	STRINGID_TERRAINBECOMESMISTY 497
+#define	STRINGID_TERRAINBECOMESGRASSY 498
+#define	STRINGID_TERRAINBECOMESELECTRIC 499
+#define	STRINGID_TERRAINBECOMESPSYCHIC 500
 
 #define BATTLESTRINGS_COUNT     516
 
diff --git a/include/data/battle_moves.h b/include/data/battle_moves.h
index 74ed8974dc..fb5ca5b63c 100644
--- a/include/data/battle_moves.h
+++ b/include/data/battle_moves.h
@@ -5200,7 +5200,7 @@ const struct BattleMove gBattleMoves[MOVES_COUNT_GEN6] =
 		.split = SPLIT_STATUS,
 	},
 	{ // MOVE_TRICK_ROOM
-		.effect = EFFECT_TRICK_TOOM,
+		.effect = EFFECT_TRICK_ROOM,
 		.power = 0,
 		.type = TYPE_PSYCHIC,
 		.accuracy = 0,
@@ -6965,7 +6965,7 @@ const struct BattleMove gBattleMoves[MOVES_COUNT_GEN6] =
 		.split = SPLIT_STATUS,
 	},
 	{ // MOVE_GRASSY_TERRAIN
-		.effect = EFFECT_PLACEHOLDER, // Needs a custom move effect
+		.effect = EFFECT_GRASSY_TERRAIN,
 		.power = 0,
 		.type = TYPE_GRASS,
 		.accuracy = 0,
@@ -6977,7 +6977,7 @@ const struct BattleMove gBattleMoves[MOVES_COUNT_GEN6] =
 		.split = SPLIT_STATUS,
 	},
 	{ // MOVE_MISTY_TERRAIN
-		.effect = EFFECT_PLACEHOLDER, // Needs a custom move effect
+		.effect = EFFECT_MISTY_TERRAIN,
 		.power = 0,
 		.type = TYPE_FAIRY,
 		.accuracy = 0,
@@ -7253,7 +7253,7 @@ const struct BattleMove gBattleMoves[MOVES_COUNT_GEN6] =
 		.split = SPLIT_STATUS,
 	},
 	{ // MOVE_ELECTRIC_TERRAIN
-		.effect = EFFECT_PLACEHOLDER, // Needs a custom move effect
+		.effect = EFFECT_ELECTRIC_TERRAIN,
 		.power = 0,
 		.type = TYPE_ELECTRIC,
 		.accuracy = 0,
diff --git a/src/battle_message.c b/src/battle_message.c
index fbf8f516da..4c011cced5 100644
--- a/src/battle_message.c
+++ b/src/battle_message.c
@@ -628,13 +628,19 @@ static const u8 sText_TargetStatWontGoHigher[] = _("{B_DEF_NAME_WITH_PREFIX}’s
 static const u8 sText_PkmnMoveBouncedViaAbility[] = _("{B_ATK_NAME_WITH_PREFIX}’s {B_CURRENT_MOVE} was\nbounced back by {B_DEF_NAME_WITH_PREFIX}’s\l{B_DEF_ABILITY}!");
 static const u8 sText_ImposterTransform[] = _("{B_ATK_NAME_WITH_PREFIX} transformed into\n{B_DEF_NAME_WITH_PREFIX} using {B_LAST_ABILITY}!");
 static const u8 sText_NotDoneYet[] = _("This move effect is not done yet!\p");
-static const u8 sText_StickyWebUsed[] = _("");
-static const u8 sText_QuashSuccess[] = _("");
 static const u8 sText_PkmnBlewAwayToxicSpikes[] = _("{B_ATK_NAME_WITH_PREFIX} blew away\nTOXIC SPIKES!");
 static const u8 sText_PkmnBlewAwayStickyWeb[] = _("{B_ATK_NAME_WITH_PREFIX} blew away\nSTICKY WEB!");
 static const u8 sText_PkmnBlewAwayStealthRock[] = _("{B_ATK_NAME_WITH_PREFIX} blew away\nSTEALTH ROCK!");
+
+// To do.
+static const u8 sText_StickyWebUsed[] = _("");
+static const u8 sText_QuashSuccess[] = _("");
 static const u8 sText_IonDelugeOn[] = _("");
 static const u8 sText_TopsyTurvySwitchedStats[] = _("");
+static const u8 sText_TerrainBecomesMisty[] = _("");
+static const u8 sText_TerrainBecomesGrassy[] = _("");
+static const u8 sText_TerrainBecomesElectric[] = _("");
+static const u8 sText_TerrainBecomesPsychic[] = _("");
 
 // New selection strings, they must end with "\p".
 // Use {B_LAST_ITEM} and {B_CURRENT_MOVE}.
@@ -1130,6 +1136,15 @@ const u8 *const gBattleStringsTable[BATTLESTRINGS_COUNT] =
     sText_PkmnBlewAwayStealthRock,
     sText_IonDelugeOn,
     sText_TopsyTurvySwitchedStats,
+    sText_TerrainBecomesMisty,
+    sText_TerrainBecomesGrassy,
+    sText_TerrainBecomesElectric,
+    sText_TerrainBecomesPsychic,
+};
+
+const u16 gTerrainStringIds[] =
+{
+    STRINGID_TERRAINBECOMESMISTY, STRINGID_TERRAINBECOMESGRASSY, STRINGID_TERRAINBECOMESELECTRIC, STRINGID_TERRAINBECOMESPSYCHIC
 };
 
 const u16 gMagicCoatBounceStringIds[] =
diff --git a/src/battle_script_commands.c b/src/battle_script_commands.c
index df89ddd92b..1740d9c389 100644
--- a/src/battle_script_commands.c
+++ b/src/battle_script_commands.c
@@ -6058,6 +6058,44 @@ static bool32 HasAttackerFaintedTarget(void)
         return FALSE;
 }
 
+static void HandleTerrainMove(u32 moveEffect)
+{
+    u32 statusFlag = 0;
+    u8 *timer = NULL;
+
+    switch (moveEffect)
+    {
+    case EFFECT_MISTY_TERRAIN:
+        statusFlag = STATUS_FIELD_MISTY_TERRAIN, timer = &gFieldTimers.mistyTerrainTimer;
+        gBattleCommunication[MULTISTRING_CHOOSER] = 0;
+        break;
+    case EFFECT_GRASSY_TERRAIN:
+        statusFlag = STATUS_FIELD_GRASSY_TERRAIN, timer = &gFieldTimers.grassyTerrainTimer;
+        gBattleCommunication[MULTISTRING_CHOOSER] = 1;
+        break;
+    case EFFECT_ELECTRIC_TERRAIN:
+        statusFlag = STATUS_FIELD_ELECTRIC_TERRAIN, timer = &gFieldTimers.electricTerrainTimer;
+        gBattleCommunication[MULTISTRING_CHOOSER] = 2;
+        break;
+    case EFFECT_PSYCHIC_TERRAIN:
+        statusFlag = STATUS_FIELD_PSYCHIC_TERRAIN, timer = &gFieldTimers.psychicTerrainTimer;
+        gBattleCommunication[MULTISTRING_CHOOSER] = 3;
+        break;
+    }
+
+    if (gFieldStatuses & statusFlag || statusFlag == 0)
+    {
+        gBattlescriptCurrInstr = T1_READ_PTR(gBattlescriptCurrInstr + 3);
+    }
+    else
+    {
+        gFieldStatuses &= ~(STATUS_FIELD_MISTY_TERRAIN | STATUS_FIELD_GRASSY_TERRAIN | EFFECT_ELECTRIC_TERRAIN | EFFECT_PSYCHIC_TERRAIN);
+        gFieldStatuses |= statusFlag;
+        *timer = 5;
+        gBattlescriptCurrInstr += 7;
+    }
+}
+
 static void atk76_various(void)
 {
     u8 side;
@@ -6439,6 +6477,9 @@ static void atk76_various(void)
                 gBattleMons[gActiveBattler].statStages[i] = 6 - (gBattleMons[gActiveBattler].statStages[i] - 6);
         }
         break;
+    case VARIOUS_SET_TERRAIN:
+        HandleTerrainMove(gBattleMoves[gCurrentMove].effect);
+        return;
     }
 
     gBattlescriptCurrInstr += 3;
@@ -9289,15 +9330,15 @@ static void HandleRoomMove(u32 statusFlag, u8 *timer, u8 stringId)
 
 static void atkD9_setroom(void)
 {
-    switch (gCurrentMove)
+    switch (gBattleMoves[gCurrentMove].effect)
     {
-    case MOVE_TRICK_ROOM:
+    case EFFECT_TRICK_ROOM:
         HandleRoomMove(STATUS_FIELD_TRICK_ROOM, &gFieldTimers.trickRoomTimer, 0);
         break;
-    case MOVE_WONDER_ROOM:
+    case EFFECT_WONDER_ROOM:
         HandleRoomMove(STATUS_FIELD_WONDER_ROOM, &gFieldTimers.wonderRoomTimer, 2);
         break;
-    case MOVE_MAGIC_ROOM:
+    case EFFECT_MAGIC_ROOM:
         HandleRoomMove(STATUS_FIELD_MAGIC_ROOM, &gFieldTimers.magicRoomTimer, 4);
         break;
     default: