President Joe Biden delivered a sharp rebuke of Republicans during a speech in Philadelphia on Thursday evening, saying they "thrive on chaos" and warned that America's democratic values are under attack by extremists loyal to former President Donald Trump. This led social media users to share a new "Dark Brandon" meme praising the president.

Last year, the phrase "Let's go Brandon" made its way into the US political discourse after a reporter, while talking with a Nascar racer, misquoted a crowd chanting an obscenity about Biden. The disguised insult has since been used at Republican campaign rallies, on the floor of Congress and at QAnon events.

In recent months, a new meme has been making the rounds on social media, and it's even being pushed by members of the Biden administration: Dark Brandon. The conflation of a phrase intended to insult the president has ended up being a celebratory term used by Biden supporters to tout the administration's successes, such as the lowering of gas prices, the death of al-Qaida leader Ayman al-Zawahri and the cancellation of up to $20,000 in folks' student loans. 

Here's everything you need to know about the Dark Brandon meme.

What's Dark Brandon?

According to Know Your Meme, the phrase "Dark Brandon" originated in March when a person on Twitter riffed on movie titles by adding the name "Brandon," which stemmed from the "Let's go Brandon" phrase. 

In May 2021, another person shared a post on Twitter with images of purported Chinese propaganda against Biden. The illustrations show Biden, with yellow glowing eyes, sitting on a throne of AR-15s that looks like the Iron Throne from the HBO series Game of Thrones. Some Biden supporters liked the images, saying how they looked so "metal." 

The meme began gaining momentum in July and early August, especially after the lowering of gas prices, the death of al-Qaida leader Ayman al-Zawahri and the passage of the CHIPS and Science Act and the Inflation Reduction Act. 

Some people are also sharing Dark Brandon memes in reference to the FBI raid on former President Donald Trump's Mar-a-Lago estate, even though the Biden administration reportedly wasn't briefed on this law enforcement action. 

How did Let's go Brandon start? 

Last October, Brandon Brown won his first Xfinity Series Nascar race at the Talladega Superspeedway. NBC Sports reporter Kelli Stavast interviewed Brown following his win on the race track with a crowd behind him chanting "Fuck Joe Biden," which has been often chanted at US sporting events over the past several months.

During the interview, Stavast remarks about the crowd saying, "You can hear the chants from the crowd. Let's go Brandon."

It's unclear whether she mistakenly heard the phrase or decided not to repeat the term due to the profanity in the chant. 

Conservatives and others opposed to Biden's presidency seized on the phrase. It has since been used as a chant at political events and placed on merchandise from shirts to gun parts. 

What did social media companies do about the Let's go Brandon hashtag? 

Not much. Facebook, Twitter, Instagram, YouTube and TIkTok didn't remove posts with the Let's go Brandon hashtag. 

"Let's Go Brandon" trended on Twitter multiple times since the initial interview last October, with Republican politicians such as Sen. Ted Cruz, a Republican from Texas, and Rep. Lauren Boebert, a Republican from Colorado, using the hashtag, with the latter even putting the phrase on a dress. Cruz and Boebert were among the 147 Republicans who voted to overturn the 2020 presidential election results. 

To counter the phrase, fans of Biden began using the hashtag #ThankYouBrandon, which was trending on Twitter last November. 

One company that reportedly did take steps in banning the hashtag is the fitness company Peloton. A report from right-wing website PJ Media shows the hashtag isn't available to be added to user profiles. Peloton customers can use tags in their profiles to associate with others members with similar interests. 

"We have a zero tolerance policy against divisive, explicit, or other content that violates our policies," the company said in an email statement Monday. "We actively moderate our channels and have removed tags that span the political spectrum, while still allowing members to express themselves using tags like #WomenForTrump."

What've been some controversies surrounding the Let's go Brandon hashtag? 

Aside from the obvious insult of Biden, the Let's go Brandon hashtag has come with its share of controversy. 

A pilot for Southwest Airlines is under investigation over the use of the phrase during a flight announcement. 

Billboard released its list of best-selling songs for the week on Nov. 8, 2021, and two of the top five songs referenced the phrase: Bryson Gray featuring Tyson James and Chandler Crump "Let's go Brandon" and Loza Alexander's "Let's go Brandon." Gray said on his song was removed from YouTube due to medical misinformation.