diff --git a/app/controllers/mod/moderator_controller.rb b/app/controllers/mod/moderator_controller.rb
new file mode 100644
index 0000000000..39d26a3f44
--- /dev/null
+++ b/app/controllers/mod/moderator_controller.rb
@@ -0,0 +1,3 @@
+class Mod::ModeratorController < ApplicationController
+  before_action :require_logged_in_moderator
+end
diff --git a/app/controllers/mod/reparents_controller.rb b/app/controllers/mod/reparents_controller.rb
new file mode 100644
index 0000000000..3883fa6bf5
--- /dev/null
+++ b/app/controllers/mod/reparents_controller.rb
@@ -0,0 +1,35 @@
+class Mod::ReparentsController < Mod::ModeratorController
+  before_action :require_logged_in_admin
+  before_action :load_user
+
+  def new
+  end
+
+  def create
+    if params[:reason].blank?
+      return redirect_to new_mod_reparent_path({}, id: @reparent_user), flash: {error: "Reason can't be blank."}
+    end
+
+    User.transaction do
+      ModNote.record_reparent!(@reparent_user, @user, params[:reason])
+      @reparent_user.invited_by_user = @user
+      @reparent_user.save!
+      Moderation.create!({
+        moderator: @user,
+        user: @reparent_user,
+        action: "Reparented user to be invited by #{@user.username}",
+        reason: params[:reason]
+      })
+    end
+    Rails.cache.delete("users_tree_#{User.last.id}") # UsersController#tree
+
+    redirect_to user_path(@reparent_user), flash: {success: "User been has reparented to you."}
+  end
+
+  private
+
+  def load_user
+    params.require(:id)
+    @reparent_user = User.find_by! username: params[:id]
+  end
+end
diff --git a/app/controllers/users_controller.rb b/app/controllers/users_controller.rb
index 98336b9232..31c64091ac 100644
--- a/app/controllers/users_controller.rb
+++ b/app/controllers/users_controller.rb
@@ -50,7 +50,8 @@ def tree
       @title = "Moderators and Administrators"
       render action: "list"
     else
-      content = Rails.cache.fetch("users_tree_#{newest_user}", expires_in: (60 * 60 * 24)) {
+      # Mod::ReparentsController#create knows this key
+      content = Rails.cache.fetch("users_tree_#{newest_user}", expires_in: 12.hours) {
         users = User.select(*attrs).order("id DESC").to_a
         @user_count = users.length
         @users_by_parent = users.group_by(&:invited_by_user_id)
diff --git a/app/models/mod_note.rb b/app/models/mod_note.rb
index 6d281a33ee..bb841a4287 100644
--- a/app/models/mod_note.rb
+++ b/app/models/mod_note.rb
@@ -53,6 +53,28 @@ def self.create_from_message(message, moderator)
     )
   end
 
+  def self.record_reparent!(reparent_user, mod, reason)
+    old_inviter_url = Rails.application.routes.url_helpers.user_url(
+      reparent_user.invited_by_user,
+      host: Rails.application.domain
+    )
+    create_without_dupe!(
+      moderator: mod,
+      user: reparent_user,
+      note: "Reparented from [#{reparent_user.invited_by_user.username}](#{old_inviter_url}) to #{mod.username} with reason: #{reason}"
+    )
+
+    reparent_user_url = Rails.application.routes.url_helpers.user_url(
+      reparent_user,
+      host: Rails.application.domain
+    )
+    create_without_dupe!(
+      moderator: mod,
+      user: reparent_user.invited_by_user,
+      note: "Admin reparented their invitee [#{reparent_user.username}](#{reparent_user_url}) to #{mod.username} with reason: #{reason}"
+    )
+  end
+
   def self.tattle_on_banned_login(user)
     # rubocop:disable Rails/SaveBang
     create(
diff --git a/app/views/mod/reparents/new.html.erb b/app/views/mod/reparents/new.html.erb
new file mode 100644
index 0000000000..74e455fddb
--- /dev/null
+++ b/app/views/mod/reparents/new.html.erb
@@ -0,0 +1,20 @@
+<h1>Reparent <%= @reparent_user.username %></h1>
+
+<%= form_with url: mod_reparents_path({}, id: @reparent_user), method: :post do |f| %>
+  <p>
+  This will reparent <%= @reparent_user.username %> to you in the invite tree, create a mod note on the user with their old inviter, and put an entry in the moderation log with the given reason.
+  </p>
+
+  <p>
+  This should be used rarely because it makes it harder to investigate sockpuppets and voting rings.
+  Currently the only known purpose is if this user was abused off-site by their inviter and we can't really do anything about it here except try to disassociate them.
+  Write a good reason here, it's going to get attention by virtue of being rare.
+  </p>
+
+  <div class="boxline">
+    <%= f.label :reason, "Reason:", :class => "required" %>
+    <%= f.text_field :reason, :size => 80 %>
+  </div>
+  <%= f.submit "Reparent" %>
+<% end %>
+
diff --git a/app/views/users/show.html.erb b/app/views/users/show.html.erb
index bcbd191fcb..0f507a9674 100644
--- a/app/views/users/show.html.erb
+++ b/app/views/users/show.html.erb
@@ -253,7 +253,7 @@
             <% if @showing_user.is_banned? %>
               <div class="boxline">
                 <%= f.label :reason, "Reason:", :class => "required" %>
-                <%= f.text_field :reason, :size => 40 %>
+                <%= f.text_field :reason, :size => 80 %>
               </div>
               <%= f.submit "Unban" %>
             <% end %>
@@ -272,7 +272,7 @@
         <%= form_with url: user_ban_path, method: :post do |f| %>
           <div class="boxline">
             <%= f.label :reason, "Reason:", :class => "required" %>
-            <%= f.text_field :reason, :size => 40 %>
+            <%= f.text_field :reason, :size => 80 %>
           </div>
           <p>
             <% if !@showing_user.is_banned? %>
@@ -284,6 +284,8 @@
           </p>
         <% end %>
       <% end %>
+
+      <%= link_to 'Reparent', new_mod_reparent_path({}, id: @showing_user) %>
     <% end %>
   <% end %>
 </div>
diff --git a/config/routes.rb b/config/routes.rb
index 9a81a92523..9e9ff57173 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -259,6 +259,10 @@
   get "/mod/notes(/:period)" => "mod_notes#index", :as => "mod_notes"
   post "/mod/notes" => "mod_notes#create"
 
+  namespace :mod do
+    resources :reparents, only: [:new, :create]
+  end
+
   get "/privacy" => "about#privacy"
   get "/about" => "about#about"
   get "/chat" => "about#chat"
diff --git a/spec/requests/mod/reparents_spec.rb b/spec/requests/mod/reparents_spec.rb
new file mode 100644
index 0000000000..ed000ebc0d
--- /dev/null
+++ b/spec/requests/mod/reparents_spec.rb
@@ -0,0 +1,27 @@
+# typed: false
+
+require "rails_helper"
+
+describe "Mod::ReparentsController", type: :request do
+  context "/new form" do
+    it "loads" do
+      sign_in create(:user, :admin)
+      reparent_user = create(:user)
+      get "/mod/reparents/new", params: {id: reparent_user.username}
+      expect(response).to be_successful
+    end
+  end
+
+  context "reparenting" do
+    it "reparents the user and logs it" do
+      sign_in create(:user, :admin)
+      inviter = create(:user)
+      reparent_user = create(:user, invited_by_user: inviter)
+      post "/mod/reparents", params: {id: reparent_user.username, reason: "Abuse"}
+      expect(response).to redirect_to user_path(reparent_user)
+      reparent_user.reload
+      expect(reparent_user.invited_by_user).to_not be(inviter)
+      expect(Moderation.last.reason).to include("Abuse")
+    end
+  end
+end