diff --git a/lib/tasks/dangerous.rake b/lib/tasks/dangerous.rake
new file mode 100644
index 0000000000..bf87264de3
--- /dev/null
+++ b/lib/tasks/dangerous.rake
@@ -0,0 +1,193 @@
+# frozen_string_literal: true
+# rubocop:disable all
+
+namespace :dangerous do
+  task :back_upstream do
+    require './config/environment'
+
+    prompt = TTY::Prompt.new
+
+    exit(0) unless prompt.yes?('[1/3] Do you really want to go back to the original Mastodon?', default: false)
+    exit(0) unless prompt.yes?('[2/3] All proprietary data of kmyblue will be deleted and cannot be restored. Are you sure?', default: false)
+    exit(0) unless prompt.yes?('[3/3] This operation is irreversible. You have backups in case this operation causes a system malfunction, do you not?', default: false)
+
+    target_migrations = %w(
+      20231022074913
+      20231021005339
+      20230314120530
+      20240109035435
+      20231214225249
+      20231212225737
+      20231130083634
+      20231130031209
+      20231115001356
+      20231105225839
+      20231028005948
+      20231028004612
+      20231023083359
+      20231009235215
+      20231007090808
+      20231006030102
+      20231005074832
+      20231001050733
+      20231001031337
+      20230930233930
+      20230923103430
+      20230919232836
+      20230911022527
+      20230826023400
+      20230821061713
+      20230819084858
+      20230812130612
+      20230812083752
+      20230804222017
+      20230714004824
+      20230706031715
+      20230705232953
+      20230522093135
+      20230522082252
+      20230521122642
+      20230514030455
+      20230512122757
+      20230510033040
+      20230510004621
+      20230510000439
+      20230509045358
+      20230430110057
+      20230428111230
+      20230427233749
+      20230427122753
+      20230427072650
+      20230427022606
+      20230426013738
+      20230423233429
+      20230423002728
+      20230420081634
+      20230414010523
+      20230412073021
+      20230412005311
+      20230410004651
+      20230406041523
+      20230405121625
+      20230405121613
+      20230320234918
+      20230314121142
+      20230314081013
+      20230314021909
+      20230308061833
+      20230223102416
+      20230222232121
+    )
+    target_tables = %w(
+      account_groups
+      antennas
+      antenna_accounts
+      antenna_domains
+      antenna_tags
+      bookmark_categories
+      bookmark_category_statuses
+      circles
+      circle_accounts
+      circle_statuses
+      emoji_reactions
+      friend_domains
+      instance_infos
+      list_statuses
+      scheduled_expiration_statuses
+      status_capability_tokens
+      status_references
+    )
+    target_table_columns = [
+      # Removed: accounts dissubscribable
+      %w(accounts group_allow_private_message),
+      # Removed: accounts group_message_following_only
+      %w(accounts master_settings),
+      %w(accounts searchability),
+      %w(accounts settings),
+      # Removed: accounts stop_emoji_reaction_streaming
+      %w(account_stats group_activitypub_count),
+      %w(account_statuses_cleanup_policies keep_self_emoji),
+      %w(account_statuses_cleanup_policies min_emojis),
+      %w(conversations ancestor_status_id),
+      %w(conversations inbox_url),
+      %w(custom_emojis aliases),
+      %w(custom_emojis image_height),
+      %w(custom_emojis image_width),
+      %w(custom_emojis is_sensitive),
+      %w(custom_emojis license),
+      %w(custom_filters exclude_follows),
+      %w(custom_filters exclude_localusers),
+      %w(custom_filters with_quote),
+      %w(domain_blocks detect_invalid_subscription),
+      %w(domain_blocks hidden),
+      # Removed: domain_blocks hidden_anonymous
+      %w(domain_blocks reject_favourite),
+      %w(domain_blocks reject_friend),
+      %w(domain_blocks reject_hashtag),
+      %w(domain_blocks reject_new_follow),
+      %w(domain_blocks reject_reply),
+      %w(domain_blocks reject_reply_exclude_followers),
+      %w(domain_blocks reject_send_dissubscribable),
+      %w(domain_blocks reject_send_media),
+      %w(domain_blocks reject_send_not_public_searchability),
+      %w(domain_blocks reject_send_public_unlisted),
+      # Removed: domain_blocks reject_send_unlisted_dissubscribable
+      %w(domain_blocks reject_send_sensitive),
+      %w(domain_blocks reject_straight_follow),
+      %w(lists notify),
+      %w(statuses limited_scope),
+      %w(statuses markdown),
+      %w(statuses quote_of_id),
+      %w(statuses searchability),
+      %w(status_edits markdown),
+      %w(status_stats emoji_reactions),
+      %w(status_stats emoji_reactions_count),
+      %w(status_stats emoji_reaction_accounts_count),
+      %w(status_stats status_referred_by_count),
+      %w(status_stats test),
+    ]
+    target_indices = %w(
+      index_statuses_on_url
+      index_statuses_on_conversation_id
+    )
+
+    prompt.say 'Processing...'
+    ActiveRecord::Base.connection.execute('UPDATE statuses SET visibility = 1 WHERE visibility IN (10, 11)')
+    ActiveRecord::Base.connection.execute('UPDATE custom_filters SET action = 0 WHERE action = 2')
+    ActiveRecord::Base.connection.execute('UPDATE account_warnings SET action = 1250 WHERE action = 1200')
+    ActiveRecord::Base.connection.execute('CREATE INDEX IF NOT EXISTS index_statuses_local_20190824 ON statuses USING btree (id DESC, account_id) WHERE (local OR (uri IS NULL)) AND deleted_at IS NULL AND visibility = 0 AND reblog_of_id IS NULL AND ((NOT reply) OR (in_reply_to_account_id = account_id))')
+    ActiveRecord::Base.connection.execute('CREATE INDEX IF NOT EXISTS index_statuses_public_20200119 ON statuses USING btree (id DESC, account_id) WHERE deleted_at IS NULL AND visibility = 0 AND reblog_of_id IS NULL AND ((NOT reply) OR (in_reply_to_account_id = account_id))')
+    ActiveRecord::Base.connection.execute('DROP INDEX IF EXISTS index_statuses_local_20231213')
+    ActiveRecord::Base.connection.execute('DROP INDEX IF EXISTS index_statuses_public_20231213')
+    ActiveRecord::Base.connection.execute('ALTER TABLE ONLY custom_filter_keywords ALTER COLUMN whole_word SET DEFAULT true')
+    prompt.ok 'Proceed'
+
+    prompt.say 'Removing migration histories...'
+    ActiveRecord::Base.connection.execute("DELETE FROM schema_migrations WHERE version IN ('#{target_migrations.join("','")}')")
+    prompt.ok 'Removed'
+
+    prompt.say 'Removing tables...'
+    target_tables.each do |table_name|
+      ActiveRecord::Base.connection.execute("DROP TABLE IF EXISTS #{table_name} CASCADE")
+    end
+    prompt.ok 'Removed'
+
+    prompt.say 'Removing table columns...'
+    target_table_columns.each do |table_name, column_name|
+      ActiveRecord::Base.connection.execute("ALTER TABLE #{table_name} DROP COLUMN IF EXISTS #{column_name}")
+    end
+    prompt.ok 'Removed'
+
+    prompt.say 'Removing indices...'
+    target_indices.each do |index_name|
+      ActiveRecord::Base.connection.execute("DROP INDEX IF EXISTS #{index_name}")
+    end
+    prompt.ok 'Removed'
+
+    prompt.ok 'Done!'
+    prompt.say "\n"
+    prompt.ok 'Thanks for using kmyblue. Good bye!'
+  end
+end
+
+# rubocop:enable all