diff --git a/data/battle_scripts_1.s b/data/battle_scripts_1.s
index 0dc88eb43..47cbf3091 100644
--- a/data/battle_scripts_1.s
+++ b/data/battle_scripts_1.s
@@ -410,6 +410,51 @@ gBattleScriptsForMoveEffects::
 	.4byte BattleScript_EffectHit                     @ EFFECT_RISING_VOLTAGE
 	.4byte BattleScript_EffectHit                     @ EFFECT_BEAK_BLAST
 	.4byte BattleScript_EffectCourtChange             @ EFFECT_COURT_CHANGE
+	.4byte BattleScript_EffectSteelBeam               @ EFFECT_STEEL_BEAM
+
+BattleScript_EffectSteelBeam::
+	attackcanceler
+	attackstring
+	ppreduce
+	accuracycheck BattleScript_SteelBeamMiss, ACC_CURR_MOVE
+	critcalc
+	damagecalc
+	adjustdamage
+	attackanimation
+	waitanimation
+	effectivenesssound
+	hitanimation BS_TARGET
+	waitstate
+	healthbarupdate BS_TARGET
+	datahpupdate BS_TARGET
+	critmessage
+	waitmessage B_WAIT_TIME_LONG
+	resultmessage
+	waitmessage B_WAIT_TIME_LONG
+	seteffectwithchance
+	jumpifability BS_ATTACKER, ABILITY_MAGIC_GUARD, BattleScript_SteelBeamAfterSelfDamage
+	call BattleScript_SteelBeamSelfDamage
+BattleScript_SteelBeamAfterSelfDamage::
+	waitstate
+	tryfaintmon BS_ATTACKER
+	tryfaintmon BS_TARGET
+	goto BattleScript_MoveEnd
+BattleScript_SteelBeamMiss::
+	pause B_WAIT_TIME_SHORT
+	effectivenesssound
+	resultmessage
+	waitmessage B_WAIT_TIME_LONG
+	jumpifability BS_ATTACKER, ABILITY_MAGIC_GUARD, BattleScript_MoveEnd
+	bichalfword gMoveResultFlags, MOVE_RESULT_MISSED
+	call BattleScript_SteelBeamSelfDamage
+	orhalfword gMoveResultFlags, MOVE_RESULT_MISSED
+	goto BattleScript_SteelBeamAfterSelfDamage
+
+BattleScript_SteelBeamSelfDamage::
+	dmg_1_2_attackerhp
+	healthbarupdate BS_ATTACKER
+	datahpupdate BS_ATTACKER
+	return
 
 BattleScript_EffectCourtChange::
 	attackcanceler
diff --git a/include/constants/battle_move_effects.h b/include/constants/battle_move_effects.h
index 3cc3d72b3..c3460bcfe 100644
--- a/include/constants/battle_move_effects.h
+++ b/include/constants/battle_move_effects.h
@@ -393,7 +393,8 @@
 #define EFFECT_RISING_VOLTAGE 387
 #define EFFECT_BEAK_BLAST 388
 #define EFFECT_COURT_CHANGE 389
+#define EFFECT_STEEL_BEAM 390
 
-#define NUM_BATTLE_MOVE_EFFECTS 390
+#define NUM_BATTLE_MOVE_EFFECTS 391
 
 #endif  // GUARD_CONSTANTS_BATTLE_MOVE_EFFECTS_H
diff --git a/src/battle_script_commands.c b/src/battle_script_commands.c
index 227d2f573..cb60447ed 100644
--- a/src/battle_script_commands.c
+++ b/src/battle_script_commands.c
@@ -9882,7 +9882,7 @@ static void Cmd_manipulatedamage(void)
         gBattleMoveDamage = GetDrainedBigRootHp(gBattlerAttacker, gBattleMoveDamage);
         break;
     case DMG_1_2_ATTACKER_HP:
-        gBattleMoveDamage = gBattleMons[gBattlerAttacker].maxHP / 2;
+        gBattleMoveDamage = (gBattleMons[gBattlerAttacker].maxHP + 1) / 2; // Half of Max HP Rounded UP
         break;
     case DMG_RECOIL_FROM_IMMUNE:
         gBattleMoveDamage = gBattleMons[gBattlerTarget].maxHP / 2;
diff --git a/src/data/battle_moves.h b/src/data/battle_moves.h
index 1f90abf03..2035acff7 100644
--- a/src/data/battle_moves.h
+++ b/src/data/battle_moves.h
@@ -11221,7 +11221,7 @@ const struct BattleMove gBattleMoves[MOVES_COUNT] =
 
     [MOVE_STEEL_BEAM] =
     {
-        .effect = EFFECT_RECOIL_50,
+        .effect = EFFECT_STEEL_BEAM,
         .power = 140,
         .type = TYPE_STEEL,
         .accuracy = 95,