This was a fun one! Possibly not the most enjoyable screen to stare at for long periods of time, however, it would effectively communicate to the user that they've stumbled on a broken link. Something I find frustrating on a lot of 404 pages is the lack of CTA, so I was sure to include that here.

See the coded pen version:
http://codepen.io/colinspencedesign/full/oYKbJg/