The video shows Ocasio-Cortez and fellow Boston University students dancing to a segment of Lisztomania by Phoenix.
"Here is America's favorite commie know-it-all acting like the clueless nitwit she is," read the tweet from @AnonymousQ1776, who incorrectly said it was from her high school days. The account and the post have both since been deleted.
If the tweet was an attempt to humiliate Ocasio-Cortez, it failed. Many people, including an array of celebrities, tweeted their support.
"She'll never recover from the world seeing her… (watches video) …dancing adorably and having fun with her friends in high school?" wrote comedian Patton Oswalt.
Ocasio-Cortez tweeted a video response on Friday, revealing that she's still dancing to the tune of Edwin Star's 1970 song War.
"I hear the GOP thinks women dancing are scandalous. Wait till they find out Congresswomen dance too! Have a great weekend everyone," she wrote with the video.
Eric Baker, who shot the video along with classmate Julian Jensen when they were students at Boston University, explained on Friday that they were student ambassadors at the Howard Thurman Center with Ocasio-Cortez and others when they decided to make their own version of the dance, according to BU Today's report.
Baker reportedly said Ocasio-Cortez was a friend and "sort of the face of the Thurman Center" because she was good at rallying people to want to join the center.
Ocasio-Cortez, who told 60 Minutes that she's happy to be called a "radical" politician, has been the target of attacks from right-wing media since her surprise primary victory over incumbent Joseph Crowley, The Washington Post noted.
She also had the dubious honor of being the only Democrat booed by Republicans when she voted for Nancy Pelosi as speaker on Thursday.
"Over 200 members voted for Nancy Pelosi today, yet the GOP only booed one: me," she tweeted in response. "Don't hate me cause you ain't me, fellas."
The clip also inspired a Twitter account called AOC Dances to Every Song, which embellishes the video with music ranging from David Bowie's Rebel Rebel to the theme tune of anime classic Neon Genesis Evangelion.
CNET's Marrian Zhou contributed to this report.
First published at 8:46 a.m. PT.
Update, 9:36 a.m. PT: Adds Ocasio-Cortez response and GOP booing.
Update, 1:53 p.m. PT: Adds more background information on the making of the dance video.
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