diff --git a/specs/usdf_zdoom.txt b/specs/usdf_zdoom.txt
index 217354292..839f9753a 100644
--- a/specs/usdf_zdoom.txt
+++ b/specs/usdf_zdoom.txt
@@ -63,6 +63,10 @@ either refuse loading dialogues with the 'ZDoom' namespace or if it does not
 outright abort on incompatible namespaces fail with a type mismatch error on
 one of the specified propeties.
 
+In addition ZDoom defines one new field in the top level of a conversation block:
+
+id = <integer>; 	Assigns a conversation ID for use in Thing_SetConversation or in UDMF's 'conversation' actor property.
+
 ZDoom-format dialogues need to start with the line:
 
 namespace = "ZDoom";
diff --git a/src/thingdef/thingdef_codeptr.cpp b/src/thingdef/thingdef_codeptr.cpp
index 9bca87c1d..ce929b9ce 100644
--- a/src/thingdef/thingdef_codeptr.cpp
+++ b/src/thingdef/thingdef_codeptr.cpp
@@ -4578,6 +4578,7 @@ enum T_Flags
 	TF_NODESTFOG =		0x00000080, // Don't spawn any fog at the arrival position.
 	TF_USEACTORFOG =	0x00000100, // Use the actor's TeleFogSourceType and TeleFogDestType fogs.
 	TF_NOJUMP =			0x00000200, // Don't jump after teleporting.
+	TF_OVERRIDE =		0x00000400, // Ignore NOTELEPORT.
 };
 
 DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_Teleport)
@@ -4593,14 +4594,17 @@ DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_Teleport)
 
 	AActor *ref = COPY_AAPTR(self, ptr);
 
+	ACTION_SET_RESULT(false);
 	if (!ref)
 	{
 		ACTION_SET_RESULT(false);
-		return 0;
+		return numret;
 	}
 
-	if (ref->flags2 & MF2_NOTELEPORT)
-		return 0;
+	if ((ref->flags2 & MF2_NOTELEPORT) && !(Flags & TF_OVERRIDE))
+	{
+		return numret;
+	}
 
 	// Randomly choose not to teleport like A_Srcr2Decide.
 	if (flags & TF_RANDOMDECIDE)
diff --git a/wadsrc/static/actors/constants.txt b/wadsrc/static/actors/constants.txt
index f0b2233dd..88dce63bc 100644
--- a/wadsrc/static/actors/constants.txt
+++ b/wadsrc/static/actors/constants.txt
@@ -199,6 +199,7 @@ enum
 	TF_NODESTFOG =		0x00000080, // Don't spawn any fog at the arrival position.
 	TF_USEACTORFOG =	0x00000100, // Use the actor's TeleFogSourceType and TeleFogDestType fogs.
 	TF_NOJUMP =			0x00000200, // Don't jump after teleporting.
+	TF_OVERRIDE =		0x00000400, // Ignore NOTELEPORT.
 
 	TF_KEEPORIENTATION = TF_KEEPVELOCITY|TF_KEEPANGLE,
 	TF_NOFOG = TF_NOSRCFOG|TF_NODESTFOG,