diff --git a/data/battle_scripts_1.s b/data/battle_scripts_1.s
index 8f898f1d23..d5d5707ff5 100644
--- a/data/battle_scripts_1.s
+++ b/data/battle_scripts_1.s
@@ -570,9 +570,7 @@ BattleScript_ScaleShotPrintStrings::
 	printstring STRINGID_HITXTIMES
 	waitmessage 0x40
 BattleScript_ScaleShotEnd::
-	setmoveeffect MOVE_EFFECT_SPD_PLUS_1 | MOVE_EFFECT_AFFECTS_USER
-	seteffectwithchance
-	setmoveeffect MOVE_EFFECT_DEF_MINUS_1 | MOVE_EFFECT_AFFECTS_USER
+	setmoveeffect MOVE_EFFECT_SCALE_SHOT | MOVE_EFFECT_AFFECTS_USER | MOVE_EFFECT_CERTAIN
 	seteffectwithchance
 	tryfaintmon BS_TARGET, FALSE, NULL
 	moveendcase MOVEEND_SYNCHRONIZE_TARGET
@@ -7182,6 +7180,26 @@ BattleScript_DefSpDefDownTrySpDef::
 BattleScript_DefSpDefDownRet::
 	return
 
+BattleScript_DefDownSpeedUp::
+	jumpifstat BS_ATTACKER, CMP_GREATER_THAN, STAT_DEF, MIN_STAT_STAGE, BattleScript_DefDownSpeedUpTryDef
+	jumpifstat BS_ATTACKER, CMP_EQUAL, STAT_SPEED, MAX_STAT_STAGE, BattleScript_DefDownSpeedUpRet
+BattleScript_DefDownSpeedUpTryDef::
+	playstatchangeanimation BS_ATTACKER, BIT_DEF, STAT_CHANGE_NEGATIVE | STAT_CHANGE_CANT_PREVENT
+	setstatchanger STAT_DEF, 1, TRUE
+	statbuffchange MOVE_EFFECT_AFFECTS_USER | STAT_BUFF_ALLOW_PTR | MOVE_EFFECT_CERTAIN, BattleScript_DefDownSpeedUpTrySpeed
+	jumpifbyte CMP_EQUAL, cMULTISTRING_CHOOSER, B_MSG_STAT_WONT_INCREASE, BattleScript_DefDownSpeedUpTrySpeed
+	printfromtable gStatUpStringIds
+	waitmessage B_WAIT_TIME_LONG
+BattleScript_DefDownSpeedUpTrySpeed:
+	playstatchangeanimation BS_ATTACKER, BIT_SPEED, 0
+	setstatchanger STAT_SPEED, 1, FALSE
+	statbuffchange MOVE_EFFECT_AFFECTS_USER | STAT_BUFF_ALLOW_PTR | MOVE_EFFECT_CERTAIN, BattleScript_DefDownSpeedUpRet
+	jumpifbyte CMP_EQUAL, cMULTISTRING_CHOOSER, B_MSG_STAT_WONT_INCREASE, BattleScript_DefDownSpeedUpRet
+	printfromtable gStatUpStringIds
+	waitmessage B_WAIT_TIME_LONG
+BattleScript_DefDownSpeedUpRet::
+	return
+
 BattleScript_KnockedOff::
 	playanimation BS_TARGET, B_ANIM_ITEM_KNOCKOFF, NULL
 	printstring STRINGID_PKMNKNOCKEDOFF
diff --git a/include/battle_scripts.h b/include/battle_scripts.h
index 1c130b90fe..7dfc1a6da7 100644
--- a/include/battle_scripts.h
+++ b/include/battle_scripts.h
@@ -421,5 +421,6 @@ extern const u8 BattleScript_BeakBlastBurn[];
 extern const u8 BattleScript_ShellTrapSetUp[];
 extern const u8 BattleScript_ShellTrapExplode[];
 extern const u8 BattleScript_EffectShellTrap[];
+extern const u8 BattleScript_DefDownSpeedUp[];
 
 #endif // GUARD_BATTLE_SCRIPTS_H
diff --git a/include/constants/battle.h b/include/constants/battle.h
index 515d4ac027..46b6494b28 100644
--- a/include/constants/battle.h
+++ b/include/constants/battle.h
@@ -359,9 +359,9 @@
 #define MOVE_EFFECT_RECOIL_HP_25        0x46
 #define MOVE_EFFECT_RELIC_SONG          0x47
 #define MOVE_EFFECT_TRAP_BOTH           0x48
-#define MOVE_EFFECT_SPD_PLUS_1_DEF_MINUS_1 0x49
+#define MOVE_EFFECT_SCALE_SHOT          0x49
 #define MOVE_EFFECT_MELT_ITEM           0x4A
-#define NUM_MOVE_EFFECTS                0x50
+#define NUM_MOVE_EFFECTS                0x4B
 
 #define MOVE_EFFECT_AFFECTS_USER        0x4000
 #define MOVE_EFFECT_CERTAIN             0x8000
diff --git a/src/battle_main.c b/src/battle_main.c
index c394076539..25ac66be50 100644
--- a/src/battle_main.c
+++ b/src/battle_main.c
@@ -4715,8 +4715,8 @@ static void CheckFocusPunch_ClearVarsBeforeTurnStarts(void)
                     BattleScriptExecute(BattleScript_BeakBlastSetUp);
                     return;
                 case MOVE_SHELL_TRAP:
-                        BattleScriptExecute(BattleScript_ShellTrapSetUp);
-                        return;
+                    BattleScriptExecute(BattleScript_ShellTrapSetUp);
+                    return;
                 }
             }
         }
diff --git a/src/battle_script_commands.c b/src/battle_script_commands.c
index 232b976979..0aa068a995 100644
--- a/src/battle_script_commands.c
+++ b/src/battle_script_commands.c
@@ -3489,6 +3489,10 @@ void SetMoveEffect(bool32 primary, u32 certain)
                 gBattleMons[gBattlerTarget].status2 |= STATUS2_ESCAPE_PREVENTION;
                 gBattleMons[gBattlerAttacker].status2 |= STATUS2_ESCAPE_PREVENTION;
                 break;
+            case MOVE_EFFECT_SCALE_SHOT:
+                BattleScriptPush(gBattlescriptCurrInstr + 1);
+                gBattlescriptCurrInstr = BattleScript_DefDownSpeedUp;
+                break;
             }
         }
     }
@@ -9329,6 +9333,9 @@ static void Cmd_various(void)
     case VARIOUS_SET_BEAK_BLAST:    
         gProtectStructs[gBattlerAttacker].beakBlastCharge = 1;
         break;
+    case VARIOUS_SET_SHELL_TRAP:
+        gProtectStructs[gBattlerAttacker].shellTrap = 1;
+        break;
     case VARIOUS_SWAP_SIDE_STATUSES:
     {
         /* This code is a mess, but idk how to do it better without changing how Side Statuses and