diff --git a/docs/rh-log.txt b/docs/rh-log.txt
index 1e6b1e883..c819c3897 100644
--- a/docs/rh-log.txt
+++ b/docs/rh-log.txt
@@ -1,4 +1,6 @@
 October 9, 2009  (Changes by Graf Zahl)
+- added a NULL pointer check to fog spawning in unmorphing code.
+- fixed: frozen corpses need to be treated as solid by z-movement code.
 - fixed: AAmbientSound::Serialize was adjusting its timer value for savegames
   even when it was set to a 'don't check' value.
 
diff --git a/src/g_shared/a_morph.cpp b/src/g_shared/a_morph.cpp
index f12c36aef..917ae5a92 100644
--- a/src/g_shared/a_morph.cpp
+++ b/src/g_shared/a_morph.cpp
@@ -314,7 +314,10 @@ bool P_UndoPlayerMorph (player_t *activator, player_t *player, int unmorphflag,
 	}
 
 	angle = mo->angle >> ANGLETOFINESHIFT;
-	Spawn(exit_flash, pmo->x + 20*finecosine[angle], pmo->y + 20*finesine[angle], pmo->z + TELEFOGHEIGHT, ALLOW_REPLACE);
+	if (exit_flash != NULL)
+	{
+		Spawn(exit_flash, pmo->x + 20*finecosine[angle], pmo->y + 20*finesine[angle], pmo->z + TELEFOGHEIGHT, ALLOW_REPLACE);
+	}
 	mo->SetupWeaponSlots();		// Use original class's weapon slots.
 	beastweap = player->ReadyWeapon;
 	if (player->PremorphWeapon != NULL)
diff --git a/src/p_map.cpp b/src/p_map.cpp
index 8bd38498c..fe7f5f790 100644
--- a/src/p_map.cpp
+++ b/src/p_map.cpp
@@ -1441,10 +1441,15 @@ bool P_TestMobjZ (AActor *actor, bool quick, AActor **pOnmobj)
 		{ // Can't hit thing
 			continue;
 		}
-		if (thing->flags & (MF_SPECIAL|MF_NOCLIP|MF_CORPSE))
-		{ // [RH] Corpses and specials and noclippers don't block moves
+		if (thing->flags & (MF_SPECIAL|MF_NOCLIP))
+		{ // [RH] Specials and noclippers don't block moves
 			continue;
 		}
+		if (thing->flags & (MF_CORPSE))
+		{ // Corpses need a few more checks
+			if (!(actor->flags & MF_ICECORPSE))
+				continue;
+		}
 		if (!(thing->flags4 & MF4_ACTLIKEBRIDGE) && (actor->flags & MF_SPECIAL))
 		{ // [RH] Only bridges block pickup items
 			continue;
@@ -4315,10 +4320,15 @@ void P_FindAboveIntersectors (AActor *actor)
 		{ // Can't hit thing
 			continue;
 		}
-		if (thing->flags & (MF_CORPSE|MF_SPECIAL))
+		if (thing->flags & (MF_SPECIAL))
 		{ // [RH] Corpses and specials don't block moves
 			continue;
 		}
+		if (thing->flags & (MF_CORPSE))
+		{ // Corpses need a few more checks
+			if (!(actor->flags & MF_ICECORPSE))
+				continue;
+		}
 		if (thing == actor)
 		{ // Don't clip against self
 			continue;
@@ -4364,10 +4374,15 @@ void P_FindBelowIntersectors (AActor *actor)
 		{ // Can't hit thing
 			continue;
 		}
-		if (thing->flags & (MF_CORPSE|MF_SPECIAL))
+		if (thing->flags & (MF_SPECIAL))
 		{ // [RH] Corpses and specials don't block moves
 			continue;
 		}
+		if (thing->flags & (MF_CORPSE))
+		{ // Corpses need a few more checks
+			if (!(actor->flags & MF_ICECORPSE))
+				continue;
+		}
 		if (thing == actor)
 		{ // Don't clip against self
 			continue;
diff --git a/src/s_advsound.cpp b/src/s_advsound.cpp
index 11c541f45..14742f55d 100644
--- a/src/s_advsound.cpp
+++ b/src/s_advsound.cpp
@@ -1940,7 +1940,7 @@ void AAmbientSound::Serialize (FArchive &arc)
 		else
 		{
 			arc << NextCheck;
-			if (checktime != INT_MAX)
+			if (NextCheck != INT_MAX)
 			{
 				NextCheck += gametic;
 			}