diff --git a/include/constants/battle_move_effects.h b/include/constants/battle_move_effects.h
index 156db2d6af..5da278110f 100644
--- a/include/constants/battle_move_effects.h
+++ b/include/constants/battle_move_effects.h
@@ -353,6 +353,7 @@ enum {
     EFFECT_TERA_STARSTORM,
     EFFECT_DRAGON_DARTS,
     EFFECT_GUARDIAN_OF_ALOLA,
+    EFFECT_SHELL_SIDE_ARM,
     NUM_BATTLE_MOVE_EFFECTS,
 };
 
diff --git a/src/battle_ai_util.c b/src/battle_ai_util.c
index 6fb3a83506..54172f9193 100644
--- a/src/battle_ai_util.c
+++ b/src/battle_ai_util.c
@@ -541,9 +541,9 @@ struct SimulatedDamage AI_CalcDamage(u32 move, u32 battlerAtk, u32 battlerDef, u
     }
 
     if (gMovesInfo[move].effect == EFFECT_PHOTON_GEYSER)
-        gBattleStruct->swapDamageCategory = (GetCategoryBasedOnStats(gBattlerAttacker) == DAMAGE_CATEGORY_PHYSICAL);
-    else if (move == MOVE_SHELL_SIDE_ARM && gBattleStruct->shellSideArmCategory[battlerAtk][battlerDef] == DAMAGE_CATEGORY_PHYSICAL)
-        gBattleStruct->swapDamageCategory = TRUE;
+        gBattleStruct->swapDamageCategory = (GetCategoryBasedOnStats(gBattlerAttacker) != gMovesInfo[gCurrentMove].category);
+    else if (gMovesInfo[move].effect == EFFECT_SHELL_SIDE_ARM)
+        gBattleStruct->swapDamageCategory = (gBattleStruct->shellSideArmCategory[battlerAtk][battlerDef] != gMovesInfo[gCurrentMove].category);
     else if (gMovesInfo[move].effect == EFFECT_NATURE_POWER)
         move = GetNaturePowerMove(battlerAtk);
 
diff --git a/src/battle_script_commands.c b/src/battle_script_commands.c
index 9907edbe86..d77e42d368 100644
--- a/src/battle_script_commands.c
+++ b/src/battle_script_commands.c
@@ -1962,8 +1962,8 @@ static void Cmd_damagecalc(void)
     u8 moveType;
 
     GET_MOVE_TYPE(gCurrentMove, moveType);
-    if (gBattleStruct->shellSideArmCategory[gBattlerAttacker][gBattlerTarget] == DAMAGE_CATEGORY_PHYSICAL && gCurrentMove == MOVE_SHELL_SIDE_ARM)
-        gBattleStruct->swapDamageCategory = TRUE;
+    if (gMovesInfo[gCurrentMove].effect == EFFECT_SHELL_SIDE_ARM)
+        gBattleStruct->swapDamageCategory = (gBattleStruct->shellSideArmCategory[gBattlerAttacker][gBattlerTarget] != gMovesInfo[gCurrentMove].category);
     gBattleMoveDamage = CalculateMoveDamage(gCurrentMove, gBattlerAttacker, gBattlerTarget, moveType, 0, gIsCriticalHit, TRUE, TRUE);
     gBattlescriptCurrInstr = cmd->nextInstr;
 }
@@ -16865,7 +16865,7 @@ void BS_SetPhotonGeyserCategory(void)
     NATIVE_ARGS();
     if (!((gMovesInfo[gCurrentMove].effect == EFFECT_TERA_BLAST && GetActiveGimmick(gBattlerAttacker) != GIMMICK_TERA)
             || (gMovesInfo[gCurrentMove].effect == EFFECT_TERA_STARSTORM && GetActiveGimmick(gBattlerAttacker) != GIMMICK_TERA && gBattleMons[gBattlerAttacker].species == SPECIES_TERAPAGOS_STELLAR)))
-        gBattleStruct->swapDamageCategory = (GetCategoryBasedOnStats(gBattlerAttacker) == DAMAGE_CATEGORY_PHYSICAL);
+        gBattleStruct->swapDamageCategory = (GetCategoryBasedOnStats(gBattlerAttacker) != gMovesInfo[gCurrentMove].category);
     gBattlescriptCurrInstr = cmd->nextInstr;
 }
 
diff --git a/src/battle_util.c b/src/battle_util.c
index cba5c49711..01e4c9e559 100644
--- a/src/battle_util.c
+++ b/src/battle_util.c
@@ -8456,7 +8456,7 @@ bool32 IsMoveMakingContact(u32 move, u32 battlerAtk)
 
     if (!gMovesInfo[move].makesContact)
     {
-        if (move == MOVE_SHELL_SIDE_ARM && gBattleStruct->shellSideArmCategory[battlerAtk][gBattlerTarget] == DAMAGE_CATEGORY_PHYSICAL)
+        if (gMovesInfo[move].effect == EFFECT_SHELL_SIDE_ARM && gBattleStruct->shellSideArmCategory[battlerAtk][gBattlerTarget] == DAMAGE_CATEGORY_PHYSICAL)
             return TRUE;
         else
             return FALSE;
@@ -8496,7 +8496,8 @@ bool32 IsBattlerProtected(u32 battlerAtk, u32 battlerDef, u32 move)
     // Protective Pads doesn't stop Unseen Fist from bypassing Protect effects, so IsMoveMakingContact() isn't used here.
     // This means extra logic is needed to handle Shell Side Arm.
     if (GetBattlerAbility(gBattlerAttacker) == ABILITY_UNSEEN_FIST
-     && (gMovesInfo[move].makesContact || (move == MOVE_SHELL_SIDE_ARM && gBattleStruct->shellSideArmCategory[battlerAtk][battlerDef] == DAMAGE_CATEGORY_PHYSICAL))
+     && (gMovesInfo[move].makesContact
+     || (gMovesInfo[move].effect == EFFECT_SHELL_SIDE_ARM && gBattleStruct->shellSideArmCategory[battlerAtk][battlerDef] == DAMAGE_CATEGORY_PHYSICAL))
      && !gProtectStructs[battlerDef].maxGuarded) // Max Guard cannot be bypassed by Unseen Fist
         return FALSE;
     else if (gMovesInfo[move].ignoresProtect)
@@ -10990,10 +10991,17 @@ bool32 ShouldGetStatBadgeBoost(u16 badgeFlag, u32 battler)
     return FALSE;
 }
 
+static u32 SwapMoveDamageCategory(u32 move)
+{
+    if (gMovesInfo[move].category == DAMAGE_CATEGORY_PHYSICAL)
+        return DAMAGE_CATEGORY_SPECIAL;
+    return DAMAGE_CATEGORY_PHYSICAL;
+}
+
 u8 GetBattleMoveCategory(u32 moveId)
 {
     if (gBattleStruct != NULL && gBattleStruct->swapDamageCategory) // Photon Geyser, Shell Side Arm, Light That Burns the Sky, Tera Blast
-        return DAMAGE_CATEGORY_PHYSICAL;
+        return SwapMoveDamageCategory(moveId);
     if (gBattleStruct != NULL && (IsZMove(moveId) || IsMaxMove(moveId))) // TODO: Might be buggy depending on when this is called.
         return gBattleStruct->categoryOverride;
     if (B_PHYSICAL_SPECIAL_SPLIT >= GEN_4)
diff --git a/src/data/battle_move_effects.h b/src/data/battle_move_effects.h
index 01f717b47e..f970f0e9f7 100644
--- a/src/data/battle_move_effects.h
+++ b/src/data/battle_move_effects.h
@@ -2250,4 +2250,9 @@ const struct BattleMoveEffect gBattleMoveEffects[NUM_BATTLE_MOVE_EFFECTS] =
         .battleTvScore = 0, // TODO: Assign points
     },
 
+    [EFFECT_SHELL_SIDE_ARM] =
+    {
+        .battleScript = BattleScript_EffectHit,
+        .battleTvScore = 0, // TODO: Assign points
+    },
 };
diff --git a/src/data/moves_info.h b/src/data/moves_info.h
index 78dd0f118c..280a04cd4d 100644
--- a/src/data/moves_info.h
+++ b/src/data/moves_info.h
@@ -18079,7 +18079,7 @@ const struct MoveInfo gMovesInfo[MOVES_COUNT_DYNAMAX] =
         .description = COMPOUND_STRING(
             "Deals better of physical and\n"
             "special damage. May poison."),
-        .effect = EFFECT_HIT, // The effect is hardcoded to the move since SetShellSideArmCategory() can't be used with anything but Shell Side Arm because of the BP requirement
+        .effect = EFFECT_SHELL_SIDE_ARM,
         .power = 90,
         .type = TYPE_POISON,
         .accuracy = 100,
diff --git a/test/battle/move_effect/photon_geyser.c b/test/battle/move_effect/photon_geyser.c
index 3f46547ee1..986d3865aa 100644
--- a/test/battle/move_effect/photon_geyser.c
+++ b/test/battle/move_effect/photon_geyser.c
@@ -23,7 +23,7 @@ SINGLE_BATTLE_TEST("Photon Geyser can be mirror coated if it is a special move")
     }
 }
 
-SINGLE_BATTLE_TEST("Photon Geyser can be countered if it is a physcal move")
+SINGLE_BATTLE_TEST("Photon Geyser can be countered if it is a physical move")
 {
     GIVEN {
         PLAYER(SPECIES_WOBBUFFET) { Attack(110); SpAttack(100); }
diff --git a/test/battle/move_effect/shell_side_arm.c b/test/battle/move_effect/shell_side_arm.c
index f0b3dd74dc..13458e39ae 100644
--- a/test/battle/move_effect/shell_side_arm.c
+++ b/test/battle/move_effect/shell_side_arm.c
@@ -31,7 +31,7 @@ SINGLE_BATTLE_TEST("Shell Side Arm can be mirror coated if it is special")
     }
 }
 
-SINGLE_BATTLE_TEST("Shell Side Arm does not change catogory mid-turn")
+SINGLE_BATTLE_TEST("Shell Side Arm does not change category mid-turn")
 {
     s16 damage[3];
 
@@ -56,7 +56,7 @@ SINGLE_BATTLE_TEST("Shell Side Arm does not change catogory mid-turn")
     }
 }
 
-DOUBLE_BATTLE_TEST("Shell Side Arm is choosing it's type for each battler on the field")
+DOUBLE_BATTLE_TEST("Shell Side Arm chooses its category for each battler on the field")
 {
     GIVEN {
         PLAYER(SPECIES_WOBBUFFET) { Speed(10); Moves(MOVE_SHELL_SIDE_ARM); }