diff --git a/src/g_inventory/a_artifacts.cpp b/src/g_inventory/a_artifacts.cpp
index 0cd4828b1..8b57d4fe2 100644
--- a/src/g_inventory/a_artifacts.cpp
+++ b/src/g_inventory/a_artifacts.cpp
@@ -422,124 +422,6 @@ void APowerup::OwnerDied ()
 	Destroy ();
 }
 
-// Invulnerability Powerup ---------------------------------------------------
-
-IMPLEMENT_CLASS(APowerInvulnerable, false, false)
-
-//===========================================================================
-//
-// APowerInvulnerable :: InitEffect
-//
-//===========================================================================
-
-void APowerInvulnerable::InitEffect ()
-{
-	Super::InitEffect();
-	Owner->effects &= ~FX_RESPAWNINVUL;
-	Owner->flags2 |= MF2_INVULNERABLE;
-	if (Mode == NAME_None && Owner->IsKindOf(RUNTIME_CLASS(APlayerPawn)))
-	{
-		Mode = static_cast<PClassPlayerPawn *>(Owner->GetClass())->InvulMode;
-	}
-	if (Mode == NAME_Reflective)
-	{
-		Owner->flags2 |= MF2_REFLECTIVE;
-	}
-}
-
-//===========================================================================
-//
-// APowerInvulnerable :: DoEffect
-//
-//===========================================================================
-
-void APowerInvulnerable::DoEffect ()
-{
-	Super::DoEffect ();
-
-	if (Owner == NULL)
-	{
-		return;
-	}
-
-	if (Mode == NAME_Ghost)
-	{
-		if (!(Owner->flags & MF_SHADOW))
-		{
-			// Don't mess with the translucency settings if an
-			// invisibility powerup is active.
-			Owner->RenderStyle = STYLE_Translucent;
-			if (!(level.time & 7) && Owner->Alpha > 0 && Owner->Alpha < 1)
-			{
-				if (Owner->Alpha == HX_SHADOW)
-				{
-					Owner->Alpha = HX_ALTSHADOW;
-				}
-				else
-				{
-					Owner->Alpha = 0;
-					Owner->flags2 |= MF2_NONSHOOTABLE;
-				}
-			}
-			if (!(level.time & 31))
-			{
-				if (Owner->Alpha == 0)
-				{
-					Owner->flags2 &= ~MF2_NONSHOOTABLE;
-					Owner->Alpha = HX_ALTSHADOW;
-				}
-				else
-				{
-					Owner->Alpha = HX_SHADOW;
-				}
-			}
-		}
-		else
-		{
-			Owner->flags2 &= ~MF2_NONSHOOTABLE;
-		}
-	}
-}
-
-//===========================================================================
-//
-// APowerInvulnerable :: EndEffect
-//
-//===========================================================================
-
-void APowerInvulnerable::EndEffect ()
-{
-	Super::EndEffect();
-
-	if (Owner == NULL)
-	{
-		return;
-	}
-
-	Owner->flags2 &= ~MF2_INVULNERABLE;
-	Owner->effects &= ~FX_RESPAWNINVUL;
-	if (Mode == NAME_Ghost)
-	{
-		Owner->flags2 &= ~MF2_NONSHOOTABLE;
-		if (!(Owner->flags & MF_SHADOW))
-		{
-			// Don't mess with the translucency settings if an
-			// invisibility powerup is active.
-			Owner->RenderStyle = STYLE_Normal;
-			Owner->Alpha = 1.;
-		}
-	}
-	else if (Mode == NAME_Reflective)
-	{
-		Owner->flags2 &= ~MF2_REFLECTIVE;
-	}
-
-	if (Owner->player != NULL)
-	{
-		Owner->player->fixedcolormap = NOFIXEDCOLORMAP;
-	}
-}
-
 // Speed Powerup -------------------------------------------------------------
 
 IMPLEMENT_CLASS(APowerSpeed, false, false)
diff --git a/src/g_inventory/a_artifacts.h b/src/g_inventory/a_artifacts.h
index f947e18d5..89088a0be 100644
--- a/src/g_inventory/a_artifacts.h
+++ b/src/g_inventory/a_artifacts.h
@@ -57,15 +57,6 @@ public:
 	double Strength;		// Meaning depends on powerup - currently used only by Invisibility
 };
 
-class APowerInvulnerable : public APowerup
-{
-	DECLARE_CLASS (APowerInvulnerable, APowerup)
-protected:
-	virtual void InitEffect () override;
-	virtual void DoEffect () override;
-	virtual void EndEffect () override;
-};
-
 class APowerSpeed : public APowerup
 {
 	DECLARE_CLASS (APowerSpeed, APowerup)
diff --git a/src/p_mobj.cpp b/src/p_mobj.cpp
index 9c18ea638..48393caaa 100644
--- a/src/p_mobj.cpp
+++ b/src/p_mobj.cpp
@@ -5373,7 +5373,7 @@ APlayerPawn *P_SpawnPlayer (FPlayerStart *mthing, int playernum, int flags)
 		(dmflags2 & DF2_YES_RESPAWN_INVUL) &&
 		(multiplayer || alwaysapplydmflags))
 	{
-		APowerup *invul = static_cast<APowerup*>(p->mo->GiveInventoryType (RUNTIME_CLASS(APowerInvulnerable)));
+		APowerup *invul = static_cast<APowerup*>(p->mo->GiveInventoryType (PClass::FindActor(NAME_PowerInvulnerable)));
 		invul->EffectTics = 3*TICRATE;
 		invul->BlendColor = 0;			// don't mess with the view
 		invul->ItemFlags |= IF_UNDROPPABLE;	// Don't drop this
diff --git a/src/scripting/thingdef_data.cpp b/src/scripting/thingdef_data.cpp
index a3f5c144c..b99d6e646 100644
--- a/src/scripting/thingdef_data.cpp
+++ b/src/scripting/thingdef_data.cpp
@@ -100,6 +100,7 @@ static FFlagDef InternalActorFlagDefs[]=
 	DEFINE_FLAG(MF6, INTRYMOVE, AActor, flags6),
 	DEFINE_FLAG(MF7, HANDLENODELAY, AActor, flags7),
 	DEFINE_FLAG(MF7, FLYCHEAT, AActor, flags7),
+	DEFINE_FLAG(FX, RESPAWNINVUL, AActor, effects),
 };
 
 
diff --git a/wadsrc/static/zscript/inventory/powerups.txt b/wadsrc/static/zscript/inventory/powerups.txt
index b744bfc97..8ad8bdac1 100644
--- a/wadsrc/static/zscript/inventory/powerups.txt
+++ b/wadsrc/static/zscript/inventory/powerups.txt
@@ -38,14 +38,134 @@ class Powerup : Inventory native
 //
 //===========================================================================
 
-class PowerInvulnerable : Powerup native
+class PowerInvulnerable : Powerup
 {
 	Default
 	{
 		Powerup.Duration -30;
 		inventory.icon "SPSHLD0";
 	}
-	
+
+	//===========================================================================
+	//
+	// APowerInvulnerable :: InitEffect
+	//
+	//===========================================================================
+
+	override void InitEffect ()
+	{
+		Super.InitEffect();
+		Owner.bRespawnInvul = false;
+		Owner.bInvulnerable = true;
+		if (Mode == 'None' && Owner is "PlayerPawn")
+		{
+			Mode = PlayerPawn(Owner).InvulMode;
+		}
+		if (Mode == 'Reflective')
+		{
+			Owner.bReflective = true;
+		}
+	}
+
+	//===========================================================================
+	//
+	// APowerInvulnerable :: DoEffect
+	//
+	//===========================================================================
+
+	override void DoEffect ()
+	{
+		Super.DoEffect ();
+
+		if (Owner == NULL)
+		{
+			return;
+		}
+
+		if (Mode == 'Ghost')
+		{
+			if (!Owner.bShadow)
+			{
+				// Don't mess with the translucency settings if an
+				// invisibility powerup is active.
+				let alpha = Owner.Alpha;
+				if (!(level.time & 7) && alpha > 0 && alpha < 1)
+				{
+					if (alpha == HX_SHADOW)
+					{
+						alpha = HX_ALTSHADOW;
+					}
+					else
+					{
+						alpha = 0;
+						Owner.bNonShootable = true;
+					}
+				}
+				if (!(level.time & 31))
+				{
+					if (alpha == 0)
+					{
+						Owner.bNonShootable = false;
+						alpha = HX_ALTSHADOW;
+					}
+					else
+					{
+						alpha = HX_SHADOW;
+					}
+				}
+				Owner.A_SetRenderStyle(alpha, STYLE_Translucent);
+			}
+			else
+			{
+				Owner.bNonShootable = false;
+			}
+		}
+	}
+
+	//===========================================================================
+	//
+	// APowerInvulnerable :: EndEffect
+	//
+	//===========================================================================
+
+	override void EndEffect ()
+	{
+		Super.EndEffect();
+
+		if (Owner == NULL)
+		{
+			return;
+		}
+
+		Owner.bRespawnInvul = false;
+		Owner.bInvulnerable = false;
+		if (Mode == 'Ghost')
+		{
+			Owner.bNonShootable = false;
+			if (!bShadow)
+			{
+				// Don't mess with the translucency settings if an
+				// invisibility powerup is active.
+				Owner.A_SetRenderStyle(1, STYLE_Normal);
+			}
+		}
+		else if (Mode == 'Reflective')
+		{
+			Owner.bReflective = false;
+		}
+
+		if (Owner.player != NULL)
+		{
+			Owner.player.fixedcolormap = PlayerInfo.NOFIXEDCOLORMAP;
+		}
+	}
+
+	//===========================================================================
+	//
+	// APowerInvulnerable :: AlterWeaponSprite
+	//
+	//===========================================================================
+
 	override void AlterWeaponSprite (VisStyle vis, in out int changed)
 	{
 		if (Owner != NULL)