This is not the error page you aren't looking for

Tired of manually managing redirects because users can't spell? Proxy all 404 pages to your local link shortener, and let that sort it out.

ErrorDocument 404 /.404/%{sha1:%{SERVER_NAME}%{REQUEST_URI}}?%{QUERY_STRING}
RewriteRule ^/.404/(.*)$ http://sho.rt/$1 [P]

(Needs to be a [P] in order to not have a redirect to a 404 in case of non-existing page.)