Wow, those are some angry fans.
In this clip (above), the Baltimore Raven's coach John Harbaugh was signaling for the ref to come over and talk to him.
He had stepped onto the field, and, well, that's not cool - especially because the current refs are just scabs, filling in for the real refs who are locked out.
The NFL wants to keep coaches from taking advantage of these inexperienced refs (mainly because they're awful as referees) so they hit the coach with an unsportsmanlike conduct penalty. The fans, naturally, showed their displeasure with a rousing chant of "bullsh-t" that aired live on TV!
Check out the video (above) to see how coach Harbaugh tries to play off his misconduct and hear the fans react. Yikes!!