diff --git a/src/engine/fox_demo.c b/src/engine/fox_demo.c
index 41385906..7335c5ba 100644
--- a/src/engine/fox_demo.c
+++ b/src/engine/fox_demo.c
@@ -18,6 +18,7 @@
 #include "assets/ast_title.h"
 #include "assets/ast_katina.h"
 #include "assets/ast_allies.h"
+#include "port/hooks/Events.h"
 
 void func_demo_80048AC0(TeamId teamId) {
     s32 teamShield;
@@ -1567,7 +1568,9 @@ void Cutscene_DropVsItem(Player* player, ObjectId itemId, Item* item) {
     item->obj.pos.y = player->pos.y;
     item->obj.pos.z = player->trueZpos;
     item->obj.id = itemId;
-    Object_SetInfo(&item->info, item->obj.id);
+    CALL_CANCELLABLE_EVENT(ItemDropEvent, item){
+        Object_SetInfo(&item->info, item->obj.id);
+    }
 }
 
 void Cutscene_KillPlayer(Player* player) {
diff --git a/src/engine/fox_enmy.c b/src/engine/fox_enmy.c
index 3f4a7c55..0d184d14 100644
--- a/src/engine/fox_enmy.c
+++ b/src/engine/fox_enmy.c
@@ -18,6 +18,7 @@
 #include "assets/ast_training.h"
 #include "assets/ast_versus.h"
 #include "assets/ast_zoness.h"
+#include "port/hooks/Events.h"
 
 s32 D_enmy_Timer_80161670[4];
 s32 gLastPathChange;
@@ -276,7 +277,9 @@ void Item_Load(Item* this, ObjectInit* objInit) {
     this->obj.rot.z = objInit->rot.z;
     this->obj.id = objInit->id;
     this->width = 1.0f;
-    Object_SetInfo(&this->info, this->obj.id);
+    CALL_CANCELLABLE_EVENT(ItemDropEvent, this){
+        Object_SetInfo(&this->info, this->obj.id);
+    }
 }
 
 void Effect_Effect346_Setup(Effect346* this, f32 xPos, f32 yPos, f32 zPos) {
@@ -1042,7 +1045,9 @@ void Scenery_CoStoneArch_Init(CoStoneArch* this, f32* hitboxData) {
             item->obj.pos.y = this->obj.pos.y;
             item->obj.pos.z = this->obj.pos.z;
             item->obj.rot.y = this->obj.rot.y;
-            Object_SetInfo(&item->info, item->obj.id);
+            CALL_CANCELLABLE_EVENT(ItemDropEvent, item){
+                Object_SetInfo(&item->info, item->obj.id);
+            }
             item->info.hitbox = LOAD_ASSET(hitboxData);
             break;
         }
@@ -1696,7 +1701,9 @@ void func_enmy_800660F0(Actor* this) {
             item->obj.pos.z = this->obj.pos.z;
             item->timer_4A = 8;
 
-            Object_SetInfo(&item->info, item->obj.id);
+            CALL_CANCELLABLE_EVENT(ItemDropEvent, item){
+                Object_SetInfo(&item->info, item->obj.id);
+            }
 
             if ((item->obj.id == OBJ_ITEM_SILVER_RING) || (item->obj.id == OBJ_ITEM_BOMB) ||
                 (item->obj.id == OBJ_ITEM_LASERS)) {
diff --git a/src/engine/fox_play.c b/src/engine/fox_play.c
index a0f50a41..91d91fdc 100644
--- a/src/engine/fox_play.c
+++ b/src/engine/fox_play.c
@@ -21,6 +21,7 @@
 #include "assets/ast_versus.h"
 #include "assets/ast_area_6.h"
 #include "assets/ast_zoness.h"
+#include "port/hooks/Events.h"
 
 extern float gCurrentScreenWidth;
 extern float gCurrentScreenHeight;
@@ -7011,7 +7012,9 @@ void Play_SpawnVsItem(ObjectId objId, Item* item) {
             item->obj.pos.y = gScenery360[spawnIndex].obj.pos.y;
             item->obj.pos.z = gScenery360[spawnIndex].obj.pos.z;
             item->obj.id = objId;
-            Object_SetInfo(&item->info, item->obj.id);
+            CALL_CANCELLABLE_EVENT(ItemDropEvent, item){
+                Object_SetInfo(&item->info, item->obj.id);
+            }
         }
     }
 }
diff --git a/src/overlays/ovl_i1/fox_co.c b/src/overlays/ovl_i1/fox_co.c
index 07ce439e..c0a0197a 100644
--- a/src/overlays/ovl_i1/fox_co.c
+++ b/src/overlays/ovl_i1/fox_co.c
@@ -8,6 +8,7 @@
 #include "assets/ast_arwing.h"
 #include "assets/ast_corneria.h"
 #include "fox_co.h"
+#include "port/hooks/Events.h"
 
 u8 sFightCarrier;
 f32 sCoGrangaWork[68];
@@ -89,7 +90,9 @@ void Corneria_Granga_SpawnItem(Boss* this, f32 x, f32 y, f32 z, ObjectId itemId)
             gItems[i].obj.pos.x = x;
             gItems[i].obj.pos.y = y;
             gItems[i].obj.pos.z = z;
-            Object_SetInfo(&gItems[i].info, gItems[i].obj.id);
+            CALL_CANCELLABLE_EVENT(ItemDropEvent, &gItems[i]){
+                Object_SetInfo(&gItems[i].info, gItems[i].obj.id);
+            }
             break;
         }
     }
@@ -593,7 +596,9 @@ void Corneria_CoGranga_1UpCheck(CoGranga* this) {
                     gItems[i].obj.pos.z = gPlayer[0].trueZpos + dest.z;
                     gItems[i].timer_4A = 8;
 
-                    Object_SetInfo(&gItems[i].info, gItems[i].obj.id);
+                    CALL_CANCELLABLE_EVENT(ItemDropEvent, &gItems[i]){
+                        Object_SetInfo(&gItems[i].info, gItems[i].obj.id);
+                    }
                     Effect_Effect384_Spawn(gItems[i].obj.pos.x, gItems[i].obj.pos.y, gItems[i].obj.pos.z, 5.0f, 0);
                     break;
                 }
diff --git a/src/overlays/ovl_i3/fox_aq.c b/src/overlays/ovl_i3/fox_aq.c
index b5934d5c..ddda6488 100644
--- a/src/overlays/ovl_i3/fox_aq.c
+++ b/src/overlays/ovl_i3/fox_aq.c
@@ -7,6 +7,7 @@
 #include "global.h"
 #include "assets/ast_blue_marine.h"
 #include "assets/ast_aquas.h"
+#include "port/hooks/Events.h"
 // #include "prevent_bss_reordering2.h"
 
 const char D_i3_801C1A30[] = "プレイヤーのすべてをクリア \n"; // Clear of all players
@@ -380,7 +381,9 @@ void Aquas_SpawnItem(Vec3f* pos, ObjectId objId) {
             item->obj.pos.y = pos->y;
             item->obj.pos.z = pos->z;
             item->timer_4A = 2;
-            Object_SetInfo(&item->info, item->obj.id);
+            CALL_CANCELLABLE_EVENT(ItemDropEvent, item){
+                Object_SetInfo(&item->info, item->obj.id);
+            }
             break;
         }
     }
diff --git a/src/overlays/ovl_i6/fox_andross.c b/src/overlays/ovl_i6/fox_andross.c
index 5cd2bbea..d9e5cc0f 100644
--- a/src/overlays/ovl_i6/fox_andross.c
+++ b/src/overlays/ovl_i6/fox_andross.c
@@ -7,6 +7,7 @@
 #include "assets/ast_bg_planet.h"
 #include "prevent_bss_reordering.h"
 #include "prevent_bss_reordering2.h"
+#include "port/hooks/Events.h"
 
 f32 D_i6_801A7F5C;
 f32 D_i6_801A7F64;
@@ -154,7 +155,9 @@ void Andross_801878A8() {
             item->obj.pos.z = -gLevelObjects[i].zPos1;
             item->obj.pos.z += gLevelObjects[i].zPos2;
             item->obj.pos.y = gLevelObjects[i].yPos;
-            Object_SetInfo(&item->info, item->obj.id);
+            CALL_CANCELLABLE_EVENT(ItemDropEvent, item){
+                Object_SetInfo(&item->info, item->obj.id);
+            }
             item++;
         }
     }
@@ -235,7 +238,9 @@ void Andross_80187C5C(void) {
             item->obj.pos.z = -gLevelObjects[i].zPos1;
             item->obj.pos.z += gLevelObjects[i].zPos2;
             item->obj.pos.y = gLevelObjects[i].yPos;
-            Object_SetInfo(&item->info, item->obj.id);
+            CALL_CANCELLABLE_EVENT(ItemDropEvent, item){
+                Object_SetInfo(&item->info, item->obj.id);
+            }
             item++;
         }
     }
@@ -1632,7 +1637,9 @@ void Andross_Effect396_Update(Effect396* this) {
                             item->obj.pos.y = this->obj.pos.y;
                             item->obj.pos.z = this->obj.pos.z;
                             item->timer_4A = 8;
-                            Object_SetInfo(&item->info, item->obj.id);
+                            CALL_CANCELLABLE_EVENT(ItemDropEvent, item){
+                                Object_SetInfo(&item->info, item->obj.id);
+                            }
                             item->unk_50 = 90.0f;
                             break;
                         }
diff --git a/src/port/hooks/Events.h b/src/port/hooks/Events.h
index 9c56592c..d4d26279 100644
--- a/src/port/hooks/Events.h
+++ b/src/port/hooks/Events.h
@@ -1,3 +1,4 @@
 #pragma once
 
-#include "list/PlayerShotEvent.h"
+#include "list/EngineEvent.h"
+#include "list/ItemEvent.h"
\ No newline at end of file
diff --git a/src/port/hooks/impl/EventSystem.cpp b/src/port/hooks/impl/EventSystem.cpp
index f2ce527c..71eaffb5 100644
--- a/src/port/hooks/impl/EventSystem.cpp
+++ b/src/port/hooks/impl/EventSystem.cpp
@@ -1,35 +1,42 @@
 #include "EventSystem.h"
 #include <stdexcept>
+#include <algorithm>
 
 EventSystem* EventSystem::Instance = new EventSystem();
 
 ListenerID EventSystem::RegisterListener(EventID id, EventCallback callback, EventPriority priority) {
-    if(std::find_if(this->mEventListeners[id].begin(), this->mEventListeners[id].end(), [callback](EventListener listener) {
+    auto& listeners = this->mEventListeners[(uint8_t)((id >> 16) & 0xFF)][(uint16_t)(id & 0xFFFF)];
+
+    if(std::find_if(listeners.begin(), listeners.end(), [callback](EventListener listener) {
         return listener.function == callback;
-    }) != this->mEventListeners[id].end()) {
+    }) != listeners.end()) {
         throw std::runtime_error("Listener already registered");
     }
 
-    this->mEventListeners[id].push_back({ priority, callback });
+    listeners.push_back({ priority, callback });
 
     // Sort by priority
-    std::sort(this->mEventListeners[id].begin(), this->mEventListeners[id].end(), [](EventListener a, EventListener b) {
+    std::sort(listeners.begin(), listeners.end(), [](EventListener a, EventListener b) {
         return a.priority < b.priority;
     });
 
-    return this->mEventListeners[id].size() - 1;
+    return listeners.size() - 1;
 }
 
-void EventSystem::UnregisterListener(EventID ev, ListenerID id) {
-    this->mEventListeners[ev].erase(this->mEventListeners[ev].begin() + id);
+void EventSystem::UnregisterListener(EventID id, ListenerID listenerId) {
+    auto& listeners = this->mEventListeners[(uint8_t)((id >> 16) & 0xFF)][(uint16_t)(id & 0xFFFF)];
+
+    listeners.erase(listeners.begin() + listenerId);
 }
 
 void EventSystem::CallEvent(EventID id, IEvent* event) {
-    if (this->mEventListeners[id].empty()) {
+    auto& listeners = this->mEventListeners[(uint8_t)((id >> 16) & 0xFF)][(uint16_t)(id & 0xFFFF)];
+
+    if (listeners.empty()) {
         return;
     }
 
-    for (auto& listener : this->mEventListeners[id]) {
+    for (auto& listener : listeners) {
         listener.function(event);
     }
 }
diff --git a/src/port/hooks/impl/EventSystem.h b/src/port/hooks/impl/EventSystem.h
index d7f47b73..17413408 100644
--- a/src/port/hooks/impl/EventSystem.h
+++ b/src/port/hooks/impl/EventSystem.h
@@ -5,6 +5,7 @@
 #include <stddef.h>
 
 typedef uint16_t EventID;
+typedef uint16_t NamespaceID;
 typedef uint32_t ListenerID;
 
 typedef enum {
@@ -29,13 +30,32 @@ typedef struct {
     EventCallback function;
 } EventListener;
 
-// ID              Type
-// 000000000000000 0
-#define EVENT_ID(id, type) ((id << 1) | type)
+// Namespace        ID              Type
+// 00000000XXXXXXXX 000000000000000 0
+#define EVENT_ID(namespace_, id_, type_) ((((uint32_t)(namespace_) & 0xFFFF) << 16) | (((uint32_t)(id_) & 0x7FFF) << 1) | ((uint32_t)(type_) & 0x1))
+
+#define INTERNAL_EVENT_ID(id, type) EVENT_ID(0, id, type)
+#define DEFINE_EVENT(id, eventName, type, ...) \
+    typedef struct { \
+        IEvent event; \
+        __VA_ARGS__ \
+    } eventName; \
+    \
+    static uint32_t eventName##_ID = INTERNAL_EVENT_ID(id, type);
+
+#define CALL_EVENT(eventType, ...) \
+    eventType eventType##_ = { {false}, __VA_ARGS__ }; \
+    EventSystem_CallEvent(eventType##_ID, &eventType##_);
+
+#define CALL_CANCELLABLE_EVENT(eventType, ...) \
+    eventType eventType##_ = { {false}, __VA_ARGS__ }; \
+    EventSystem_CallEvent(eventType##_ID, &eventType##_); \
+    if (!eventType##_.event.cancelled)
 
 #ifdef __cplusplus
 #include <array>
 #include <vector>
+#include <unordered_map>
 
 class EventSystem {
 public:
@@ -44,7 +64,7 @@ public:
     void UnregisterListener(EventID ev, ListenerID id);
     void CallEvent(EventID id, IEvent* event);
 private:
-    std::array<std::vector<EventListener>, 0xFFFF> mEventListeners;
+    std::unordered_map<NamespaceID, std::unordered_map<EventID, std::vector<EventListener>>> mEventListeners;
 };
 #else
 extern ListenerID EventSystem_RegisterListener(EventID id, EventCallback callback, EventPriority priority);
diff --git a/src/port/hooks/list/EngineEvent.h b/src/port/hooks/list/EngineEvent.h
index 87e883f8..6b3f8f8d 100644
--- a/src/port/hooks/list/EngineEvent.h
+++ b/src/port/hooks/list/EngineEvent.h
@@ -2,8 +2,8 @@
 
 #include "port/hooks/impl/EventSystem.h"
 
-#define DISPLAY_UPDATE_EVENT_PRE  EVENT_ID(1, EVENT_TYPE_PRE)
-#define DISPLAY_UPDATE_EVENT_POST EVENT_ID(1, EVENT_TYPE_POST)
+#define DISPLAY_UPDATE_EVENT_PRE  INTERNAL_EVENT_ID(1, EVENT_TYPE_PRE)
+#define DISPLAY_UPDATE_EVENT_POST INTERNAL_EVENT_ID(1, EVENT_TYPE_POST)
 
-#define GAME_UPDATE_EVENT_PRE  EVENT_ID(2, EVENT_TYPE_PRE)
-#define GAME_UPDATE_EVENT_POST EVENT_ID(2, EVENT_TYPE_POST)
\ No newline at end of file
+#define GAME_UPDATE_EVENT_PRE  INTERNAL_EVENT_ID(2, EVENT_TYPE_PRE)
+#define GAME_UPDATE_EVENT_POST INTERNAL_EVENT_ID(2, EVENT_TYPE_POST)
\ No newline at end of file
diff --git a/src/port/hooks/list/ItemEvent.h b/src/port/hooks/list/ItemEvent.h
new file mode 100644
index 00000000..70e89a14
--- /dev/null
+++ b/src/port/hooks/list/ItemEvent.h
@@ -0,0 +1,9 @@
+#pragma once
+
+#include "gfx.h"
+#include "sf64object.h"
+#include "port/hooks/impl/EventSystem.h"
+
+DEFINE_EVENT(3, ItemDropEvent, EVENT_TYPE_PRE, 
+    Item* item;
+);
\ No newline at end of file