diff --git a/src/k_kart.c b/src/k_kart.c
index 7cafa491..146120f7 100644
--- a/src/k_kart.c
+++ b/src/k_kart.c
@@ -4021,6 +4021,7 @@ void K_RepairOrbitChain(mobj_t *orbit)
 	// Then recount to make sure item amount is correct
 	if (orbit->target && orbit->target->player)
 	{
+		player_t *player = orbit->target->player;
 		INT32 num = 0;
 
 		mobj_t *cur = orbit->target->hnext;
@@ -4030,14 +4031,14 @@ void K_RepairOrbitChain(mobj_t *orbit)
 		{
 			prev = cur;
 			cur = cur->hnext;
-			if (++num > orbit->target->player->kartstuff[k_itemamount])
+			if (++num > player->kartstuff[k_itemamount])
 				P_RemoveMobj(prev);
 			else
 				prev->movedir = num;
 		}
 
-		if (orbit->target->player->kartstuff[k_itemamount] != num)
-			orbit->target->player->kartstuff[k_itemamount] = num;
+		if (player->kartstuff[k_itemamount] != num)
+			player->kartstuff[k_itemamount] = num;
 	}
 }
 
diff --git a/src/lua_maplib.c b/src/lua_maplib.c
index 41875ea9..ae9dd4e9 100644
--- a/src/lua_maplib.c
+++ b/src/lua_maplib.c
@@ -258,6 +258,8 @@ static int lib_iterateSectorThinglist(lua_State *L)
 	if (!lua_isnil(L, 1))
 	{
 		thing = *((mobj_t **)luaL_checkudata(L, 1, META_MOBJ));
+		if (P_MobjWasRemoved(thing))
+			return luaL_error(L, "current entry in thinglist was removed; avoid calling P_RemoveMobj on entries!");
 		thing = thing->snext;
 	}
 	else
diff --git a/src/p_inter.c b/src/p_inter.c
index db321541..d4dca95f 100644
--- a/src/p_inter.c
+++ b/src/p_inter.c
@@ -3142,6 +3142,8 @@ boolean P_DamageMobj(mobj_t *target, mobj_t *inflictor, mobj_t *source, INT32 da
 		UINT8 shouldForce = LUAh_ShouldDamage(target, inflictor, source, damage);
 		if (P_MobjWasRemoved(target))
 			return (shouldForce == 1); // mobj was removed
+		if (P_MobjWasRemoved(source))
+			source = NULL;
 		if (shouldForce == 1)
 			force = true;
 		else if (shouldForce == 2)
@@ -3468,6 +3470,9 @@ boolean P_DamageMobj(mobj_t *target, mobj_t *inflictor, mobj_t *source, INT32 da
 			break;
 		}
 
+	if (P_MobjWasRemoved(target))
+		return false;
+
 	if (!P_MobjWasRemoved(target))
 	{
 		target->reactiontime = 0; // we're awake now...
diff --git a/src/p_mobj.c b/src/p_mobj.c
index 7978d0f3..f0ca3ed6 100644
--- a/src/p_mobj.c
+++ b/src/p_mobj.c
@@ -263,6 +263,9 @@ boolean P_SetMobjState(mobj_t *mobj, statenum_t state)
 		I_Error("P_SetMobjState used for player mobj. Use P_SetPlayerMobjState instead!\n(State called: %d)", state);
 #endif
 
+	if (mobj->player != NULL)
+		return P_SetPlayerMobjState(mobj, state);
+
 	if (recursion++) // if recursion detected,
 		memset(seenstate = tempstate, 0, sizeof tempstate); // clear state table
 
@@ -590,29 +593,41 @@ void P_ExplodeMissile(mobj_t *mo)
 		P_RadiusAttack(mo, mo, 96*FRACUNIT);
 
 		explodemo = P_SpawnMobj(mo->x, mo->y, mo->z, MT_EXPLODE);
-		P_SetScale(explodemo, mo->scale);
-		explodemo->destscale = mo->destscale;
-		explodemo->momx += (P_RandomByte() % 32) * FixedMul(FRACUNIT/8, explodemo->scale);
-		explodemo->momy += (P_RandomByte() % 32) * FixedMul(FRACUNIT/8, explodemo->scale);
-		S_StartSound(explodemo, sfx_pop);
+		if (!P_MobjWasRemoved(explodemo))
+		{
+			P_SetScale(explodemo, mo->scale);
+			explodemo->destscale = mo->destscale;
+			explodemo->momx += (P_RandomByte() % 32) * FixedMul(FRACUNIT/8, explodemo->scale);
+			explodemo->momy += (P_RandomByte() % 32) * FixedMul(FRACUNIT/8, explodemo->scale);
+			S_StartSound(explodemo, sfx_pop);
+		}
 		explodemo = P_SpawnMobj(mo->x, mo->y, mo->z, MT_EXPLODE);
-		P_SetScale(explodemo, mo->scale);
-		explodemo->destscale = mo->destscale;
-		explodemo->momx += (P_RandomByte() % 64) * FixedMul(FRACUNIT/8, explodemo->scale);
-		explodemo->momy -= (P_RandomByte() % 64) * FixedMul(FRACUNIT/8, explodemo->scale);
-		S_StartSound(explodemo, sfx_dmpain);
+		if (!P_MobjWasRemoved(explodemo))
+		{
+			P_SetScale(explodemo, mo->scale);
+			explodemo->destscale = mo->destscale;
+			explodemo->momx += (P_RandomByte() % 64) * FixedMul(FRACUNIT/8, explodemo->scale);
+			explodemo->momy -= (P_RandomByte() % 64) * FixedMul(FRACUNIT/8, explodemo->scale);
+			S_StartSound(explodemo, sfx_dmpain);
+		}
 		explodemo = P_SpawnMobj(mo->x, mo->y, mo->z, MT_EXPLODE);
-		P_SetScale(explodemo, mo->scale);
-		explodemo->destscale = mo->destscale;
-		explodemo->momx -= (P_RandomByte() % 128) * FixedMul(FRACUNIT/8, explodemo->scale);
-		explodemo->momy += (P_RandomByte() % 128) * FixedMul(FRACUNIT/8, explodemo->scale);
-		S_StartSound(explodemo, sfx_pop);
+		if (!P_MobjWasRemoved(explodemo))
+		{
+			P_SetScale(explodemo, mo->scale);
+			explodemo->destscale = mo->destscale;
+			explodemo->momx -= (P_RandomByte() % 128) * FixedMul(FRACUNIT/8, explodemo->scale);
+			explodemo->momy += (P_RandomByte() % 128) * FixedMul(FRACUNIT/8, explodemo->scale);
+			S_StartSound(explodemo, sfx_pop);
+		}
 		explodemo = P_SpawnMobj(mo->x, mo->y, mo->z, MT_EXPLODE);
-		P_SetScale(explodemo, mo->scale);
-		explodemo->destscale = mo->destscale;
-		explodemo->momx -= (P_RandomByte() % 96) * FixedMul(FRACUNIT/8, explodemo->scale);
-		explodemo->momy -= (P_RandomByte() % 96) * FixedMul(FRACUNIT/8, explodemo->scale);
-		S_StartSound(explodemo, sfx_cybdth);
+		if (!P_MobjWasRemoved(explodemo))
+		{
+			P_SetScale(explodemo, mo->scale);
+			explodemo->destscale = mo->destscale;
+			explodemo->momx -= (P_RandomByte() % 96) * FixedMul(FRACUNIT/8, explodemo->scale);
+			explodemo->momy -= (P_RandomByte() % 96) * FixedMul(FRACUNIT/8, explodemo->scale);
+			S_StartSound(explodemo, sfx_cybdth);
+		}
 
 		// Hack: Release an animal.
 		P_DamageMobj(mo, NULL, NULL, 10000);
@@ -3584,6 +3599,9 @@ static void P_PlayerMobjThinker(mobj_t *mobj)
 	I_Assert(mobj->player != NULL);
 	I_Assert(!P_MobjWasRemoved(mobj));
 
+	if (P_MobjWasRemoved(mobj))
+		return;
+
 	P_MobjCheckWater(mobj);
 
 	P_ButteredSlope(mobj);
@@ -7051,6 +7069,9 @@ void P_MobjThinker(mobj_t *mobj)
 	// separate thinker
 	if (mobj->flags & MF_PUSHABLE || (mobj->info->flags & MF_PUSHABLE && mobj->fuse))
 	{
+		if (P_MobjWasRemoved(mobj))
+			return;
+
 		P_MobjCheckWater(mobj);
 		P_PushableThinker(mobj);
 
@@ -10235,6 +10256,10 @@ void P_RemoveMobj(mobj_t *mobj)
 		}
 	}
 
+	// clear the reference from the mapthing
+	if (mobj->spawnpoint)
+		mobj->spawnpoint->mobj = NULL;
+
 	// free block
 	// DBG: set everything in mobj_t to 0xFF instead of leaving it. debug memory error.
 	if (mobj->flags & MF_NOTHINK && !mobj->thinker.next)
@@ -10751,6 +10776,7 @@ void P_SpawnPlayer(INT32 playernum)
 	}
 
 	mobj = P_SpawnMobj(0, 0, 0, MT_PLAYER);
+	I_Assert(mobj != NULL);
 	(mobj->player = p)->mo = mobj;
 
 	mobj->angle = 0;
@@ -11363,6 +11389,13 @@ void P_SpawnMapThing(mapthing_t *mthing)
 	}
 
 	mobj = P_SpawnMobj(x, y, z, i);
+
+	if (!mobj || P_MobjWasRemoved(mobj))
+	{
+		CONS_Alert(CONS_WARNING, "Failed to spawn map thing #%d at %d, %d\n", mthing->type, x>>FRACBITS, y>>FRACBITS);
+		return;
+	}
+
 	mobj->spawnpoint = mthing;
 
 	switch(mobj->type)
diff --git a/src/p_user.c b/src/p_user.c
index 94169754..fda7d9bb 100644
--- a/src/p_user.c
+++ b/src/p_user.c
@@ -829,6 +829,10 @@ void P_NightserizePlayer(player_t *player, INT32 nighttime)
 //
 boolean P_PlayerInPain(player_t *player)
 {
+	// If the player doesn't have a mobj, it can't be in pain.
+	if (!player->mo)
+		return false;
+
 	// no silly, sliding isn't pain
 	if (!(player->pflags & PF_SLIDING) && player->mo->state == &states[player->mo->info->painstate] && player->powers[pw_flashing])
 		return true;