diff --git a/server/gameserver/zombiemode.ai.cc b/server/gameserver/zombiemode.ai.cc
index 5cf20bf7..35ab1d48 100644
--- a/server/gameserver/zombiemode.ai.cc
+++ b/server/gameserver/zombiemode.ai.cc
@@ -31,8 +31,8 @@ public:
     int next_total_shot_times = 0;
 
     long long param1 = 0;
-    Creature* target = nullptr;
-    Creature* nearest_human = nullptr;
+    CreatureWeakPtr target;
+    CreatureWeakPtr nearest_human;
     long long last_check_nearest_human_frameno = 0;
     a8::Vec2 shot_dir;
 
@@ -157,7 +157,7 @@ void ZombieModeAI::UpdateThinking()
     } else {
         Creature* target = GetTarget();
         if (target) {
-            node_->target = target;
+            node_->target.Attach(target);
             ChangeToState(ZSE_Attack);
         } else {
             if (hum->room->GetFrameNo() >= node_->next_random_move_frameno) {
@@ -180,16 +180,16 @@ void ZombieModeAI::UpdateAttack()
     if (myself->HasBuffEffect(kBET_Vertigo)) {
         return;
     }
-    if (!node_->target || node_->target->dead) {
+    if (!node_->target.Get() || node_->target.Get()->dead) {
         ChangeToState(ZSE_Thinking);
         return;
     }
     if (node_->exec_frame_num > SERVER_FRAME_RATE * 8 ||
-        myself->GetRace() == node_->target->GetRace()) {
+        myself->GetRace() == node_->target.Get()->GetRace()) {
         ChangeToState(ZSE_Thinking);
         return;
     }
-    float distance = myself->GetPos().Distance(node_->target->GetPos());
+    float distance = myself->GetPos().Distance(node_->target.Get()->GetPos());
     if (distance > GetAttackRange()) {
         Skill* skill = myself->SelectSkill();
         if (myself->CanUseSkill(skill->meta->i->skill_id()) &&
@@ -261,7 +261,7 @@ void ZombieModeAI::UpdateRandomWalk()
 void ZombieModeAI::UpdatePursuit()
 {
     Human* myself = (Human*)owner;
-    float distance = myself->GetPos().Distance(node_->target->GetPos());
+    float distance = myself->GetPos().Distance(node_->target.Get()->GetPos());
     if (distance < GetAttackRange()) {
         ChangeToState(ZSE_Attack);
     } else {
@@ -287,11 +287,11 @@ void ZombieModeAI::DoMove()
         int speed = std::max(1, (int)hum->GetSpeed()) * 1;
         hum->_UpdateMove(speed);
         hum->on_move_collision = nullptr;
-        if (node_->nearest_human) {
+        if (node_->nearest_human.Get()) {
             if (node_->main_state != ZSE_Pursuit &&
-                hum->GetPos().ManhattanDistance(node_->nearest_human->GetPos()) < 200) {
+                hum->GetPos().ManhattanDistance(node_->nearest_human.Get()->GetPos()) < 200) {
                 ChangeToState(ZSE_Thinking);
-            } else if (hum->GetPos().ManhattanDistance(node_->nearest_human->GetPos()) > 800) {
+            } else if (hum->GetPos().ManhattanDistance(node_->nearest_human.Get()->GetPos()) > 800) {
                 GetTarget();
             }
         }
@@ -304,7 +304,7 @@ void ZombieModeAI::ChangeToState(ZombieState_e to_state)
     switch (to_state) {
     case ZSE_Idle:
         {
-            node_->target = nullptr;
+            node_->target.Reset();
             node_->param1 = 0;
             node_->start_shot_frameno = 0;
             node_->shot_times = 0;
@@ -319,7 +319,7 @@ void ZombieModeAI::ChangeToState(ZombieState_e to_state)
         break;
     case ZSE_Thinking:
         {
-            node_->target = nullptr;
+            node_->target.Reset();
             node_->param1 = 0;
             node_->start_shot_frameno = 0;
             node_->shot_times = 0;
@@ -338,7 +338,7 @@ void ZombieModeAI::ChangeToState(ZombieState_e to_state)
     case ZSE_RandomWalk:
         {
             node_->moving = true;
-            node_->target = nullptr;
+            node_->target.Reset();
             node_->param1 = SERVER_FRAME_RATE * node_->ai_meta->GetMoveTime();
             node_->start_shot_frameno = 0;
             node_->shot_times = 0;
@@ -356,8 +356,8 @@ void ZombieModeAI::ChangeToState(ZombieState_e to_state)
     case ZSE_Pursuit:
         {
             node_->moving = true;
-            if (node_->target) {
-                hum->move_dir = node_->target->GetPos() - hum->GetPos();
+            if (node_->target.Get()) {
+                hum->move_dir = node_->target.Get()->GetPos() - hum->GetPos();
                 hum->move_dir.Normalize();
                 hum->attack_dir = hum->move_dir;
             }
@@ -394,7 +394,7 @@ Creature* ZombieModeAI::GetTarget()
              }
          });
     if (target) {
-        node_->nearest_human = target;
+        node_->nearest_human.Attach(target);
         node_->last_check_nearest_human_frameno = myself->room->GetFrameNo();
         float distance = myself->GetPos().Distance(target->GetPos());
         #if 0
@@ -427,14 +427,14 @@ float ZombieModeAI::GetAttackRange()
 void ZombieModeAI::DoShot()
 {
     Human* myself = (Human*)owner;
-    if (!node_->target) {
+    if (!node_->target.Get()) {
         return;
     }
 
     bool shot_ok = false;
     a8::Vec2 shot_dir = myself->attack_dir;
     if (node_->total_shot_times >= node_->next_total_shot_times) {
-        shot_dir = node_->target->GetPos() - myself->GetPos();
+        shot_dir = node_->target.Get()->GetPos() - myself->GetPos();
         node_->next_total_shot_times += 7 + (rand() % 6);
         myself->attack_dir = shot_dir;
     }
@@ -467,7 +467,7 @@ void ZombieModeAI::DoShot()
 void ZombieModeAI::DoSkill(int skill_id)
 {
     Human* myself = (Human*)owner;
-    myself->DoSkill(skill_id, node_->target->GetEntityUniId(), a8::Vec2(), node_->target->GetPos());
+    myself->DoSkill(skill_id, node_->target.Get()->GetEntityUniId(), a8::Vec2(), node_->target.Get()->GetPos());
 }
 
 int ZombieModeAI::GetAttackTimes()