diff --git a/packages/entity/list/index.js b/packages/entity/list/index.js
index 000f163..2aed160 100644
--- a/packages/entity/list/index.js
+++ b/packages/entity/list/index.js
@@ -1,5 +1,9 @@
 import {compose, EventEmitter} from '@avocado/core';
 import {QuadTree, Rectangle, Vector} from '@avocado/math';
+import {
+  SynchronizedCreatePacket,
+  SynchronizedDestroyPacket,
+} from '@avocado/net';
 
 import {EntityListUpdateEntityPacket} from '../packets/entity-list-update-entity.packet';
 import {Entity} from '../entity.synchronized';
@@ -14,10 +18,9 @@ export class EntityList extends decorate(class {}) {
     super();
     this._afterDestructionTickers = [];
     this._entities = {};
-    this._entitiesJustAdded = [];
-    this._entitiesJustRemoved = [];
     this._entityTickers = []
     this._flatEntities = [];
+    this._informedEntities = new Map();
     this._quadTree = new QuadTree();
   }
 
@@ -41,6 +44,16 @@ export class EntityList extends decorate(class {}) {
         }
       }
     }
+    if (packet instanceof SynchronizedCreatePacket) {
+      const entity = new Entity(packet.data.spec);
+      this.addEntity(entity);
+    }
+    if (packet instanceof SynchronizedDestroyPacket) {
+      const uuid = packet.data.synchronized.id;
+      if (this._entities[uuid]) {
+        this._entities[uuid].destroy();
+      }
+    }
   }
 
   addEntity(entity) {
@@ -53,7 +66,7 @@ export class EntityList extends decorate(class {}) {
     this._flatEntities.push(entity);
     this._entityTickers.push(entity.tick);
     if (AVOCADO_SERVER) {
-      this._entitiesJustAdded.push(entity);
+      this._informedEntities.set(entity, []);
     }
     entity.setIntoList(this);
     entity.once('destroy', () => {
@@ -103,17 +116,38 @@ export class EntityList extends decorate(class {}) {
 
   packets(informed) {
     const packets = [];
+    // Visible entities.
+    const {areaToInform} = informed;
+    const previousVisibleEntities = this._informedEntities.get(informed);
+    const visibleEntities = this.visibleEntities(areaToInform);
     const updates = [];
-    for (const uuid in this._entities) {
-      const entity = this._entities[uuid];
-      const entityPackets = entity.packets(informed);
-      if (entityPackets.length > 0) {
-        updates.push({
-          uuid: entity.instanceUuid,
-          packets: entityPackets,
-        });
+    for (let i = 0; i < visibleEntities.length; i++) {
+      const entity = visibleEntities[i];
+      // Newly visible entity.
+      const index = previousVisibleEntities.indexOf(entity);
+      if (-1 === index) {
+        packets.push(entity.createPacket(informed));
+      }
+      // Still visible entity.
+      else {
+        const entityPackets = entity.packets(informed);
+        if (entityPackets.length > 0) {
+          updates.push({
+            uuid: entity.instanceUuid,
+            packets: entityPackets,
+          });
+        }
+        previousVisibleEntities.splice(index, 1);
       }
     }
+    for (let i = 0; i < previousVisibleEntities.length; i++) {
+      const entity = previousVisibleEntities[i];
+      // Newly removed entity.
+      if (-1 === visibleEntities.indexOf(entity)) {
+        packets.push(entity.destroyPacket(informed));
+      }
+    }
+    this._informedEntities.set(informed, visibleEntities);
     if (updates.length > 0) {
       packets.push(new EntityListUpdateEntityPacket(updates));
     }
@@ -130,7 +164,7 @@ export class EntityList extends decorate(class {}) {
       return;
     }
     if (AVOCADO_SERVER) {
-      this._entitiesJustRemoved.push(entity);
+      this._informedEntities.delete(entity);
     }
     entity.removeFromList();
     delete this._entities[uuid];
diff --git a/packages/net/s13n/server.js b/packages/net/s13n/server.js
index 6b572b7..50780e7 100644
--- a/packages/net/s13n/server.js
+++ b/packages/net/s13n/server.js
@@ -1,4 +1,4 @@
-import {idFromSynchronized, synchronizedFromId} from './registry';
+import {idFromSynchronized} from './registry';
 
 import {SynchronizedCreatePacket} from './synchronized-create.packet';
 import {SynchronizedDestroyPacket} from './synchronized-destroy.packet';
@@ -52,28 +52,15 @@ export class ServerSynchronizer {
     const payload = [];
     for (let i = 0; i < this._synchronizedFlat.length; i++) {
       const synchronized = this._synchronizedFlat[i];
-      const id = synchronized.synchronizationId();
-      const type = idFromSynchronized(synchronized.constructor);
       if (-1 !== this._added.indexOf(synchronized)) {
-        const packet = new SynchronizedCreatePacket({
-          synchronized: {
-            id,
-            type,
-          },
-          spec: synchronized.toNetwork(informed),
-        });
-        payload.push(packet);
+        payload.push(synchronized.createPacket(informed));
       }
       else if (-1 !== this._removed.indexOf(synchronized)) {
-        const packet = new SynchronizedDestroyPacket({
-          synchronized: {
-            id,
-            type,
-          },
-        });
-        payload.push(packet);
+        payload.push(synchronized.destroyPacket(informed));
       }
       else {
+        const id = synchronized.synchronizationId();
+        const type = idFromSynchronized(synchronized.constructor);
         const packets = synchronized.packetsFor(informed);
         for (let j = 0; j < packets.length; j++) {
           const packet = packets[j];
diff --git a/packages/net/s13n/synchronized.js b/packages/net/s13n/synchronized.js
index 1b081e1..fa7f823 100644
--- a/packages/net/s13n/synchronized.js
+++ b/packages/net/s13n/synchronized.js
@@ -1,3 +1,7 @@
+import {idFromSynchronized} from './registry';
+import {SynchronizedCreatePacket} from './synchronized-create.packet';
+import {SynchronizedDestroyPacket} from './synchronized-destroy.packet';
+
 export function SynchronizedMixin(Superclass) {
 
   return class Synchronized extends Superclass {
@@ -11,8 +15,31 @@ export function SynchronizedMixin(Superclass) {
       this._idempotentPackets = [];
     }
 
+    createPacket(informed) {
+      const id = this.synchronizationId();
+      const type = idFromSynchronized(this.constructor);
+      return new SynchronizedCreatePacket({
+        synchronized: {
+          id,
+          type,
+        },
+        spec: this.toNetwork(informed),
+      });
+    }
+
     destroy() {}
 
+    destroyPacket(informed) {
+      const id = this.synchronizationId();
+      const type = idFromSynchronized(this.constructor);
+      return new SynchronizedDestroyPacket({
+        synchronized: {
+          id,
+          type,
+        },
+      });
+    }
+
     fromNetwork(json) {
       this.fromJSON(json);
     }
diff --git a/packages/topdown/layer.js b/packages/topdown/layer.js
index f206c65..8885731 100644
--- a/packages/topdown/layer.js
+++ b/packages/topdown/layer.js
@@ -5,6 +5,10 @@ import {
   EntityListUpdateEntityPacket,
 } from '@avocado/entity';
 import {Vector} from '@avocado/math';
+import {
+  SynchronizedCreatePacket,
+  SynchronizedDestroyPacket,
+} from '@avocado/net';
 import {ShapeList} from '@avocado/physics';
 
 import {
@@ -57,6 +61,13 @@ export class Layer extends decorate(class {}) {
     if (packet instanceof EntityListUpdateEntityPacket) {
       this.entityList.acceptPacket(packet);
     }
+    // May have to check type...
+    if (packet instanceof SynchronizedCreatePacket) {
+      this.entityList.acceptPacket(packet);
+    }
+    if (packet instanceof SynchronizedDestroyPacket) {
+      this.entityList.acceptPacket(packet);
+    }
   }
 
   addEntity(entity) {