diff --git a/server/gameserver/bullet.cc b/server/gameserver/bullet.cc
index 0fb5964..9f1952f 100644
--- a/server/gameserver/bullet.cc
+++ b/server/gameserver/bullet.cc
@@ -149,12 +149,17 @@ void Bullet::ProcBomb()
             ProcC4Bomb(delay_time);
         }
         break;
+    case IS_SINGAL_GUN:
+        {
+            ProcSignalGunBomb(delay_time);
+        }
     default:
         {
         }
         break;
     }
     room->RemoveObjectLater(this);
+    later_removed_ = true;
 }
 
 void Bullet::ProcSmokeBomb()
@@ -203,11 +208,15 @@ bool Bullet::IsBomb()
         meta->i->_inventory_slot() == IS_SMOKE ||
         meta->i->_inventory_slot() == IS_POSION_GAS_BOMB ||
         meta->i->_inventory_slot() == IS_MOLOTOR_COCKTAIL ||
-        meta->i->_inventory_slot() == IS_C4;
+        meta->i->_inventory_slot() == IS_C4 ||
+        meta->i->_inventory_slot() == IS_SINGAL_GUN;
 }
 
 void Bullet::MapServiceUpdate()
 {
+    if (later_removed_) {
+        return;
+    }
     if (sender.Get()) {
         SetPos(GetPos() + dir * gun_meta->i->bullet_speed() / (float)SERVER_FRAME_RATE);
         float distance = (GetPos() - born_pos).Norm();
@@ -218,6 +227,7 @@ void Bullet::MapServiceUpdate()
                 Check(distance);
                 if (!later_removed_) {
                     room->RemoveObjectLater(this);
+                    later_removed_ = true;
                 }
             }
         } else {
@@ -380,3 +390,20 @@ void Bullet::ProcC4Bomb(int delay_time)
              );
     }
 }
+
+void Bullet::ProcSignalGunBomb(int delay_time)
+{
+    printf("%d xxxxxx\n",this);
+    if (sender.Get()) {
+        a8::Vec2 old_buff_vec2_param1 = sender.Get()->buff_vec2_param1;
+        sender.Get()->buff_vec2_param1 = GetPos();
+        MetaData::Buff * buff_meta = MetaMgr::Instance()->GetBuff(gun_meta->i->buffid());
+        if (buff_meta) {
+            sender.Get()->AddBuff(sender.Get(),
+                                  buff_meta,
+                                  1
+                                  );
+        }
+        sender.Get()->buff_vec2_param1 = old_buff_vec2_param1;
+    }
+}
diff --git a/server/gameserver/bullet.h b/server/gameserver/bullet.h
index 48a2a94..2b88b56 100644
--- a/server/gameserver/bullet.h
+++ b/server/gameserver/bullet.h
@@ -50,6 +50,7 @@ protected:
     void ProcPosionGasBomb(int delay_time);
     void ProcMolotorCocktailBomb(int delay_time);
     void ProcC4Bomb(int delay_time);
+    void ProcSignalGunBomb(int delay_time);
     inline void MapServiceUpdate();
     void Check(float distance);
 
diff --git a/server/gameserver/constant.h b/server/gameserver/constant.h
index 18f6bf3..a305ed9 100755
--- a/server/gameserver/constant.h
+++ b/server/gameserver/constant.h
@@ -335,6 +335,7 @@ enum ObstacleType_e
     kObstacleSpring = 5,
     kObstacleHideHouse = 6,
     kObstacleGully = 7,
+    kObstacleAirDropBox = 8,
 };
 
 const char* const PROJ_NAME_FMT = "game%d_gameserver";
diff --git a/server/gameserver/metadata.cc b/server/gameserver/metadata.cc
index 3e403f2..7463ce3 100644
--- a/server/gameserver/metadata.cc
+++ b/server/gameserver/metadata.cc
@@ -155,6 +155,14 @@ namespace MetaData
                 a8::SetBitFlag(receive_special_damage_type, n);
             }
         }
+        {
+            int_param1 = a8::XValue(i->param1());
+            float_param1 = a8::XValue(i->param1()).GetDouble();
+        }
+        {
+            int_param2 = a8::XValue(i->param2());
+            float_param2 = a8::XValue(i->param2()).GetDouble();
+        }
     }
 
     void Equip::Init()
diff --git a/server/gameserver/metadata.h b/server/gameserver/metadata.h
index e15a8e7..dde1b9b 100755
--- a/server/gameserver/metadata.h
+++ b/server/gameserver/metadata.h
@@ -47,6 +47,10 @@ namespace MetaData
         std::vector<int> airdrop_mon_list;
         long long special_damage_type = 0;
         long long receive_special_damage_type = 0;
+        int int_param1 = 0;
+	float float_param1 = 0;
+        int int_param2 = 0;
+	float float_param2 = 0;
 
         void Init();
     };
diff --git a/server/gameserver/roomobstacle.cc b/server/gameserver/roomobstacle.cc
index c95a01e..bddbc2e 100644
--- a/server/gameserver/roomobstacle.cc
+++ b/server/gameserver/roomobstacle.cc
@@ -364,6 +364,11 @@ void RoomObstacle::Active()
             ActiveGully();
         }
         break;
+    case kObstacleAirDropBox:
+        {
+            ActiveAirDrop();
+        }
+        break;
     default:
         {
         }
@@ -506,6 +511,36 @@ void RoomObstacle::ActiveGully()
 
 }
 
+void RoomObstacle::ActiveAirDrop()
+{
+    room->xtimer.AddDeadLineTimerAndAttach
+        (
+         meta->int_param2 / FRAME_RATE_MS,
+         a8::XParams()
+         .SetSender(this),
+         [] (const a8::XParams& param)
+         {
+             RoomObstacle* obstacle = (RoomObstacle*)param.sender.GetUserData();
+             obstacle->SummonAirDropBox(obstacle->meta->int_param1);
+         },
+         &xtimer_attacher.timer_list_
+         );
+    room->xtimer.AddDeadLineTimerAndAttach
+        (
+         meta->int_param2 / FRAME_RATE_MS * 1,
+         a8::XParams()
+         .SetSender(this),
+         [] (const a8::XParams& param)
+         {
+             RoomObstacle* obstacle = (RoomObstacle*)param.sender.GetUserData();
+             obstacle->room->frame_event.AddAirDrop(obstacle->meta->int_param2 / 1000,
+                                                    obstacle->meta->int_param1,
+                                                    obstacle->GetPos());
+         },
+         &xtimer_attacher.timer_list_
+         );
+}
+
 bool RoomObstacle::DoInteraction(Human* sender)
 {
     if (Obstacle::DoInteraction(sender)) {
@@ -514,3 +549,12 @@ bool RoomObstacle::DoInteraction(Human* sender)
     return true;
 }
 
+void RoomObstacle::SummonAirDropBox(int box_id)
+{
+    RoomObstacle* obstacle = room->CreateObstacle
+        (
+         box_id,
+         GetPos().x,
+         GetPos().y
+         );
+}
diff --git a/server/gameserver/roomobstacle.h b/server/gameserver/roomobstacle.h
index e4ca658..be7817f 100644
--- a/server/gameserver/roomobstacle.h
+++ b/server/gameserver/roomobstacle.h
@@ -35,6 +35,9 @@ private:
     void ActiveSpring();
     void ActiveHideHouse();
     void ActiveGully();
+    void ActiveAirDrop();
+
+    void SummonAirDropBox(int box_id);
 
 protected:
     bool temp_through_ = false;
diff --git a/server/tools/protobuild/metatable.proto b/server/tools/protobuild/metatable.proto
index 31bf741..5c9fec6 100755
--- a/server/tools/protobuild/metatable.proto
+++ b/server/tools/protobuild/metatable.proto
@@ -64,6 +64,8 @@ message MapThing
     optional string monster_list = 21;
     optional string special_damage_type = 22;
     optional string receive_special_damage_type = 23;
+    optional string param1 = 24;
+    optional string param2 = 25;
 }
 
 message SafeArea