diff --git a/src/client/Client.js b/src/client/Client.js
index 69986e071..ae40d6774 100644
--- a/src/client/Client.js
+++ b/src/client/Client.js
@@ -16,7 +16,7 @@ const VoiceRegion = require('../structures/VoiceRegion');
 const Webhook = require('../structures/Webhook');
 const User = require('../structures/User');
 const Invite = require('../structures/Invite');
-const OAuth2Application = require('../structures/OAuth2Application');
+const ClientApplication = require('../structures/ClientApplication');
 const ShardClientUtil = require('../sharding/ShardClientUtil');
 const VoiceBroadcast = require('./voice/VoiceBroadcast');
 const { Error, TypeError, RangeError } = require('../errors');
@@ -415,7 +415,7 @@ class Client extends EventEmitter {
    */
   fetchApplication(id = '@me') {
     return this.api.oauth2.applications(id).get()
-      .then(app => new OAuth2Application(this, app));
+      .then(app => new ClientApplication(this, app));
   }
 
   /**
diff --git a/src/index.js b/src/index.js
index face2be00..217bb1494 100644
--- a/src/index.js
+++ b/src/index.js
@@ -46,8 +46,7 @@ module.exports = {
   MessageEmbed: require('./structures/MessageEmbed'),
   MessageMentions: require('./structures/MessageMentions'),
   MessageReaction: require('./structures/MessageReaction'),
-  OAuth2Application: require('./structures/OAuth2Application'),
-  ClientOAuth2Application: require('./structures/OAuth2Application'),
+  ClientApplication: require('./structures/ClientApplication'),
   PartialGuild: require('./structures/PartialGuild'),
   PartialGuildChannel: require('./structures/PartialGuildChannel'),
   PermissionOverwrites: require('./structures/PermissionOverwrites'),
diff --git a/src/structures/OAuth2Application.js b/src/structures/ClientApplication.js
similarity index 80%
rename from src/structures/OAuth2Application.js
rename to src/structures/ClientApplication.js
index 15297f60e..6e00c654e 100644
--- a/src/structures/OAuth2Application.js
+++ b/src/structures/ClientApplication.js
@@ -126,7 +126,36 @@ class OAuth2Application {
    */
   iconURL({ format, size } = {}) {
     if (!this.icon) return null;
-    return Constants.Endpoints.CDN(this.client.options.http.cdn).AppIcon(this.id, this.icon, format, size);
+    return Constants.Endpoints.CDN(this.client.options.http.cdn).AppIcon(this.id, this.icon, { format, size });
+  }
+
+  /**
+   * Get rich presence assets
+   * @returns {Promise<Object>}
+   */
+  fetchAssets() {
+    return this.client.api.applications(this.id).assets.get()
+      .then(assets => assets.map(a => ({
+        id: a.id,
+        name: a.name,
+        type: Object.keys(Constants.ClientApplicationAssetTypes)[a.type - 1],
+      })));
+  }
+
+  /**
+   * Create a rich presence asset
+   * @param {string} name Name of the asset
+   * @param {Base64Resolvable} data Data of the asset
+   * @param {string} type Type of the asset. `big`, or `small`
+   * @returns {Promise}
+   */
+  createAsset(name, data, type) {
+    return this.client.resolveBase64(data).then(b64 =>
+      this.client.api.applications(this.id).assets.post({ data: {
+        name,
+        data: b64,
+        type: Constants.ClientApplicationAssetTypes[type.toUpperCase()],
+      } }));
   }
 
   /**
diff --git a/src/structures/Message.js b/src/structures/Message.js
index 97584d84d..440552f95 100644
--- a/src/structures/Message.js
+++ b/src/structures/Message.js
@@ -3,6 +3,7 @@ const Attachment = require('./MessageAttachment');
 const Embed = require('./MessageEmbed');
 const MessageReaction = require('./MessageReaction');
 const ReactionCollector = require('./ReactionCollector');
+const ClientApplication = require('./ClientApplication');
 const Util = require('../util/Util');
 const Collection = require('../util/Collection');
 const Constants = require('../util/Constants');
@@ -137,6 +138,21 @@ class Message {
      */
     this.webhookID = data.webhook_id || null;
 
+    /**
+     * Supplimental application information for group activities
+     * @type {?ClientApplication}
+     */
+    this.application = data.application ? new ClientApplication(this.client, data.application) : null;
+
+    /**
+     * Group activity
+     * @type {?Object}
+     */
+    this.activiy = data.activity ? {
+      partyID: data.activity.party_id,
+      type: data.activity.type,
+    } : null;
+
     /**
      * Whether this message is a hit in a search
      * @type {?boolean}
diff --git a/src/util/Constants.js b/src/util/Constants.js
index 0238ed483..c23af6adf 100644
--- a/src/util/Constants.js
+++ b/src/util/Constants.js
@@ -103,9 +103,10 @@ const AllowedImageSizes = [
   2048,
 ];
 
-function checkImage({ size, format }) {
+function makeImageUrl(root, { format = 'webp', size } = {}) {
   if (format && !AllowedImageFormats.includes(format)) throw new Error('IMAGE_FORMAT', format);
   if (size && !AllowedImageSizes.includes(size)) throw new RangeError('IMAGE_SIZE', size);
+  return `${root}.${format}${size ? `?size=${size}` : ''}`;
 }
 
 exports.Endpoints = {
@@ -116,25 +117,16 @@ exports.Endpoints = {
       DefaultAvatar: number => `${root}/embed/avatars/${number}.png`,
       Avatar: (userID, hash, format = 'default', size) => {
         if (format === 'default') format = hash.startsWith('a_') ? 'gif' : 'webp';
-        checkImage({ size, format });
-        return `${root}/avatars/${userID}/${hash}.${format}${size ? `?size=${size}` : ''}`;
-      },
-      Icon: (guildID, hash, format = 'webp', size) => {
-        checkImage({ size, format });
-        return `${root}/icons/${guildID}/${hash}.${format}${size ? `?size=${size}` : ''}`;
-      },
-      AppIcon: (clientID, hash, format = 'webp', size) => {
-        checkImage({ size, format });
-        return `${root}/app-icons/${clientID}/${hash}.${format}${size ? `?size=${size}` : ''}`;
-      },
-      GDMIcon: (channelID, hash, format = 'webp', size) => {
-        checkImage({ size, format });
-        return `${root}/channel-icons/${channelID}/${hash}.${format}${size ? `?size=${size}` : ''}`;
-      },
-      Splash: (guildID, hash, format = 'webp', size) => {
-        checkImage({ size, format });
-        return `${root}/splashes/${guildID}/${hash}.${format}${size ? `?size=${size}` : ''}`;
+        return makeImageUrl(`${root}/avatars/${userID}/${hash}`, { format, size });
       },
+      Icon: (guildID, hash, format = 'webp', size) =>
+        makeImageUrl(`${root}/icons/${guildID}/${hash}`, { format, size }),
+      AppIcon: (clientID, hash, { format = 'webp', size } = {}) =>
+        makeImageUrl(`${root}/app-icons/${clientID}/${hash}`, { size, format }),
+      GDMIcon: (channelID, hash, format = 'webp', size) =>
+        makeImageUrl(`${root}/channel-icons/${channelID}/${hash}`, { size, format }),
+      Splash: (guildID, hash, format = 'webp', size) =>
+        makeImageUrl(`${root}/splashes/${guildID}/${hash}`, { size, format }),
     };
   },
   invite: (root, code) => `${root}/${code}`,
@@ -570,6 +562,11 @@ exports.UserFlags = {
   HYPESQUAD: 1 << 2,
 };
 
+exports.ClientApplicationAssetTypes = {
+  SMALL: 1,
+  BIG: 2,
+};
+
 exports.Colors = {
   DEFAULT: 0x000000,
   AQUA: 0x1ABC9C,