diff --git a/src/lua_hooklib.c b/src/lua_hooklib.c
index a24473bad..eadd01537 100644
--- a/src/lua_hooklib.c
+++ b/src/lua_hooklib.c
@@ -231,6 +231,8 @@ boolean LUAh_MobjHook(mobj_t *mo, enum hook which)
 	if (!gL || !(hooksAvailable[which/8] & (1<<(which%8))))
 		return false;
 
+	I_Assert(mo->type < NUMMOBJTYPES);
+
 	lua_settop(gL, 0);
 
 	// Look for all generic mobj hooks
@@ -406,6 +408,8 @@ UINT8 LUAh_MobjCollideHook(mobj_t *thing1, mobj_t *thing2, enum hook which)
 	if (!gL || !(hooksAvailable[which/8] & (1<<(which%8))))
 		return 0;
 
+	I_Assert(thing1->type < NUMMOBJTYPES);
+
 	lua_settop(gL, 0);
 
 	// Look for all generic mobj collision hooks
@@ -479,6 +483,8 @@ boolean LUAh_MobjThinker(mobj_t *mo)
 	if (!gL || !(hooksAvailable[hook_MobjThinker/8] & (1<<(hook_MobjThinker%8))))
 		return false;
 
+	I_Assert(mo->type < NUMMOBJTYPES);
+
 	lua_settop(gL, 0);
 
 	// Look for all generic mobj thinker hooks
@@ -532,6 +538,8 @@ boolean LUAh_TouchSpecial(mobj_t *special, mobj_t *toucher)
 	if (!gL || !(hooksAvailable[hook_TouchSpecial/8] & (1<<(hook_TouchSpecial%8))))
 		return 0;
 
+	I_Assert(special->type < NUMMOBJTYPES);
+
 	lua_settop(gL, 0);
 
 	// Look for all generic touch special hooks
@@ -595,6 +603,8 @@ UINT8 LUAh_ShouldDamage(mobj_t *target, mobj_t *inflictor, mobj_t *source, INT32
 	if (!gL || !(hooksAvailable[hook_ShouldDamage/8] & (1<<(hook_ShouldDamage%8))))
 		return 0;
 
+	I_Assert(target->type < NUMMOBJTYPES);
+
 	lua_settop(gL, 0);
 
 	// Look for all generic should damage hooks
@@ -676,6 +686,8 @@ boolean LUAh_MobjDamage(mobj_t *target, mobj_t *inflictor, mobj_t *source, INT32
 	if (!gL || !(hooksAvailable[hook_MobjDamage/8] & (1<<(hook_MobjDamage%8))))
 		return 0;
 
+	I_Assert(target->type < NUMMOBJTYPES);
+
 	lua_settop(gL, 0);
 
 	// Look for all generic mobj damage hooks
@@ -747,6 +759,8 @@ boolean LUAh_MobjDeath(mobj_t *target, mobj_t *inflictor, mobj_t *source)
 	if (!gL || !(hooksAvailable[hook_MobjDeath/8] & (1<<(hook_MobjDeath%8))))
 		return 0;
 
+	I_Assert(target->type < NUMMOBJTYPES);
+
 	lua_settop(gL, 0);
 
 	// Look for all generic mobj death hooks
diff --git a/src/p_mobj.c b/src/p_mobj.c
index 7871d10cd..5f85474c6 100644
--- a/src/p_mobj.c
+++ b/src/p_mobj.c
@@ -8332,6 +8332,16 @@ void P_RespawnSpecials(void)
 			if (mthing->type == mobjinfo[i].doomednum)
 				break;
 
+		if (i == NUMMOBJTYPES) // prevent creation of objects with this type -- Monster Iestyn 17/12/17
+		{
+			// 3D Mode start Thing is unlikely to be added to the que,
+			// so don't bother checking for that specific type
+			CONS_Alert(CONS_WARNING, M_GetText("P_RespawnSpecials: Unknown thing type %d attempted to respawn at (%d, %d)\n"), mthing->type, mthing->x, mthing->y);
+			// pull it from the que
+			iquetail = (iquetail+1)&(ITEMQUESIZE-1);
+			return;
+		}
+
 		//CTF rings should continue to respawn as normal rings outside of CTF.
 		if (gametype != GT_CTF)
 		{