WASHINGTON – As candidates took the stage during the second Democratic debates in Detroit, Mich., some candidates not on stage poked fun at the assembled candidates.

Former Sen. Mike Gravel, D-Alaska, critiqued Rep. John Delaney, D-Md., who was on the stage amid some speculation he might bow out of the race amid low poll numbers.

"Currently plotting to steal @JohnDelaney staff," Gravel wrote. Gravel also invited Detroiters to come to a bar for "free food and drink," paid for by the campaign.

Gravel did not qualify for this debate.

Entrepreneur Andrew Yang wrote on Twitter, "It feels like we are about to watch the most boring football game in history."

Yang will take the stage on the second night of the Democratic debates, on Wednesday.