diff --git a/src/g_heretic/a_ironlich.cpp b/src/g_heretic/a_ironlich.cpp
index 7262db2e5..45a5640d2 100644
--- a/src/g_heretic/a_ironlich.cpp
+++ b/src/g_heretic/a_ironlich.cpp
@@ -131,8 +131,6 @@ DEFINE_ACTION_FUNCTION(AActor, A_LichAttack)
 		{
 			mo->AddZ(-32*FRACUNIT, false);
 			mo->tracer = target;
-			mo->special1 = 60;
-			mo->special2 = 50; // Timer for active sound
 			mo->health = 20*TICRATE; // Duration
 			S_Sound (self, CHAN_BODY, "ironlich/attack3", 1, ATTN_NORM);
 		}
@@ -158,9 +156,9 @@ DEFINE_ACTION_FUNCTION(AActor, A_WhirlwindSeek)
 		self->flags &= ~MF_MISSILE;
 		return 0;
 	}
-	if ((self->special2 -= 3) < 0)
+	if ((self->threshold -= 3) < 0)
 	{
-		self->special2 = 58 + (pr_seek() & 31);
+		self->threshold = 58 + (pr_seek() & 31);
 		S_Sound (self, CHAN_BODY, "ironlich/attack3", 1, ATTN_NORM);
 	}
 	if (self->tracer && self->tracer->flags&MF_SHADOW)
diff --git a/src/p_mobj.cpp b/src/p_mobj.cpp
index d47460038..a7573f4dc 100644
--- a/src/p_mobj.cpp
+++ b/src/p_mobj.cpp
@@ -1353,7 +1353,7 @@ void P_ExplodeMissile (AActor *mo, line_t *line, AActor *target)
 {
 	if (mo->flags3 & MF3_EXPLOCOUNT)
 	{
-		if (++mo->special2 < mo->special1)
+		if (++mo->threshold < mo->DefThreshold)
 		{
 			return;
 		}
diff --git a/src/p_saveg.cpp b/src/p_saveg.cpp
index cf2be64e8..f0aedd5c6 100644
--- a/src/p_saveg.cpp
+++ b/src/p_saveg.cpp
@@ -516,7 +516,7 @@ void P_SerializeWorld (FArchive &arc)
 		arc << zn->Environment;
 	}
 
-	if (SaveVersion >= 4533)
+	if (SaveVersion >= 4532)
 	{
 		arc << linePortals;
 	}
diff --git a/src/thingdef/thingdef_properties.cpp b/src/thingdef/thingdef_properties.cpp
index 5b9874a35..cecdfb172 100644
--- a/src/thingdef/thingdef_properties.cpp
+++ b/src/thingdef/thingdef_properties.cpp
@@ -547,14 +547,25 @@ DEFINE_PROPERTY(painthreshold, I, Actor)
 //==========================================================================
 //
 //==========================================================================
-DEFINE_PROPERTY(chasethreshold, I, Actor)
+DEFINE_PROPERTY(defthreshold, I, Actor)
 {
 	PROP_INT_PARM(id, 0);
 	if (id < 0)
-		I_Error("ChaseThreshold cannot be negative.");
+		I_Error("DefThreshold cannot be negative.");
 	defaults->DefThreshold = id;
 }
 
+//==========================================================================
+//
+//==========================================================================
+DEFINE_PROPERTY(threshold, I, Actor)
+{
+	PROP_INT_PARM(id, 0);
+	if (id < 0)
+		I_Error("Threshold cannot be negative.");
+	defaults->threshold = id;
+}
+
 //==========================================================================
 //
 //==========================================================================
diff --git a/wadsrc/static/actors/actor.txt b/wadsrc/static/actors/actor.txt
index 869d9dd2e..31153f2ea 100644
--- a/wadsrc/static/actors/actor.txt
+++ b/wadsrc/static/actors/actor.txt
@@ -31,7 +31,7 @@ ACTOR Actor native //: Thinker
 	RipperLevel 0
 	RipLevelMin 0
 	RipLevelMax 0
-	ChaseThreshold 100
+	DefThreshold 100
 
 	// Functions
 	native bool CheckClass(class<Actor> checkclass, int ptr_select = AAPTR_DEFAULT, bool match_superclass = false);
diff --git a/wadsrc/static/actors/heretic/ironlich.txt b/wadsrc/static/actors/heretic/ironlich.txt
index 4b3527a4f..35bd3f9b8 100644
--- a/wadsrc/static/actors/heretic/ironlich.txt
+++ b/wadsrc/static/actors/heretic/ironlich.txt
@@ -154,6 +154,8 @@ ACTOR Whirlwind native
 	+EXPLOCOUNT
 	+StepMissile
 	RenderStyle Translucent
+	DefThreshold 60
+	Threshold 50
 	Alpha 0.4
 	
 	action native A_WhirlwindSeek();