diff --git a/src/thingdef/thingdef_codeptr.cpp b/src/thingdef/thingdef_codeptr.cpp
index 642f132af..21551364b 100644
--- a/src/thingdef/thingdef_codeptr.cpp
+++ b/src/thingdef/thingdef_codeptr.cpp
@@ -231,6 +231,38 @@ DEFINE_ACTION_FUNCTION(AActor, CheckClass)
 	return 0;
 }
 
+//==========================================================================
+//
+// CheckClass
+//
+// NON-ACTION function to calculate missile damage for the given actor
+//
+//==========================================================================
+
+DEFINE_ACTION_FUNCTION(AActor, GetMissileDamage)
+{
+	if (numret > 0)
+	{
+		assert(ret != NULL);
+		PARAM_SELF_PROLOGUE(AActor);
+		PARAM_INT(mask);
+		PARAM_INT(add)
+		PARAM_INT_OPT(pick_pointer) { pick_pointer = AAPTR_DEFAULT; }
+
+		self = COPY_AAPTR(self, pick_pointer);
+		if (self == NULL)
+		{
+			ret->SetInt(0);
+		}
+		else
+		{
+			ret->SetInt(self->GetMissileDamage(mask, add));
+		}
+		return 1;
+	}
+	return 0;
+}
+
 //==========================================================================
 //
 // IsPointerEqual
diff --git a/wadsrc/static/actors/actor.txt b/wadsrc/static/actors/actor.txt
index b8bbcab14..b8b805219 100644
--- a/wadsrc/static/actors/actor.txt
+++ b/wadsrc/static/actors/actor.txt
@@ -53,6 +53,7 @@ ACTOR Actor native //: Thinker
 	native int CountProximity(class<Actor> classname, float distance, int flags = 0, int ptr = AAPTR_DEFAULT);
 	native float GetSpriteAngle(int ptr = AAPTR_DEFAULT);
 	native float GetSpriteRotation(int ptr = AAPTR_DEFAULT);
+	native int GetMissileDamage(int mask, int add, int ptr = AAPTR_DEFAULT);
 
 	// Action functions
 	// Meh, MBF redundant functions. Only for DeHackEd support.