During a weekend swing through red-state America, Sen. Bernie Sanders (I-Vt.) drew huge crowds Sunday in Houston and Dallas. The day before, he broke a new campaign attendance record in Phoenix, where 11,000 people crowded into a convention center to hear him speak.

But Sanders drew the most weekend press coverage for what many perceived as a tone-deaf response to a Black Lives Matter protest earlier Saturday in Phoenix. 

The independent candidate for the Democratic presidential nomination had been expected to receive a hero's welcome at Netroots Nation, an annual gathering of progressive activists staged this year at the Phoenix Convention Center. A group of African American activists had other ideas. They burst into the convention hall as Sanders rival Martin O'Malley, the former Democratic governor of Maryland, addressed the conference — and they didn't let up until Sanders left.

According to several media outlets, Sanders didn't handle the episode terribly gracefully.

When Sanders took the stage, according to Time, he "flashed with annoyance."

Despite watching O’Malley fumble, Sander[s] immediately began with his prepared stump speech, criticizing the media and calling for a political revolution, trying to speak over the protesters. “What are we doing here?” he grumbled to Vargas, who was unable to control the crowd. Halfway through his time, Sanders looked at the protesters and finally said “Black people are dying in this country because we have a criminal justice system that is out of control.”

CNN:

When Sanders approached the stage a moment later, the demonstrators continued. The candidate, a favorite of Netroots Nation, threatened to leave if they continued to interrupt him.

"Black lives, of course, matter. I spent 50 years of my life fighting for civil rights and for dignity," he said. "But if you don't want me to be here, that's OK. I don't want to outscream people."

The Washington Post:

The protesters remained as Sanders appeared on stage, and he took a less patient approach.

“Whoa, whoa, let me talk about what I came to talk about for a minute,” the senator said before launching into a riff on income inequality and steps to address it.

The Vermont senator faced chants and heckling as well, but Sanders continued talking. Asked what he had done in the Senate to benefit black Americans, he started to talk about the 2010 Affordable Care Act.

“We can’t afford that!” heckled Elle Hearns, a 28-year-old Ohio-based coordinator for the LGBT rights group GetEqual.

Charles Chamberlain, executive director of the Burlington-based Democracy for America, called the situation "a missed opportunity" for both O'Malley and Sanders.

"What Bernie did is he treated them as hecklers instead of a movement,” Chamberlain told Time. 

Later Saturday, according to CNN, Sanders' "tone changed" when he addressed a private fundraiser for the Latino Victory Project:

He appeared humble, and asked questions of the activists gathered about how he could better pursue and talk about policies to combat racial injustice.

"I want some help on this. I'm being very honest," Sanders said. "I want some ideas, as somebody who was arrested 50 years ago fighting for Civil Rights trying to desegregate schools in Chicago, who spent his whole life fighting against racism, I want your ideas. What do you think we can do? What can we do?"

And during his speech in Houston on Sunday, according to spokesman Michael Briggs, the candidate invoked the names of several African Americans who have died in police custody in recent years, including Sandra Bland, Eric Garner and Freddie Gray.

That didn't stop some from mocking Sanders on Twitter. 

As the Los Angeles Times' Dexter Thomas reported Sunday, the Netroots Nation incident prompted podcast host Roderick Morrow to launch the hashtag #BernieSoBlack, which mocked the candidate's backers for defending his longtime support for civil rights.

"Little known fact Bernie Sanders was actually the one who told John Carlos and Tommie Smith to put up black power fist in 68 #BernieSoBlack," Morrow tweeted.

Morrow posted a few more #BernieSoBlack tweets before leaving for work. By the time he looked at his phone two hours later, it was a trending topic.

The tweets are alternately funny and biting: Bernie’s so black he convinced Abraham Lincoln to free the slaves. Bernie’s so black he constantly gets pulled over by the police. Bernie’s so black he taught Jay-Z everything he knows.

Looks like #FeeltheBern isn't the only thing trending.