A Canadian professor mask-shamed a United Airlines flight attendant, but it backfired spectacularly when he suffered a complete meltdown online.

Amir Attaran is a professor in the Faculties of Law and School of Epidemiology and Public Health at the University of Ottawa. On Saturday, Attaran was aboard a United Airlines flight from Ottawa to Chicago, Illinois. Attaran saw that one of the flight attendants was not wearing a face mask – which goes against Canada's current travel restrictions that require travelers wear face masks when departing from Canada.

Attaran took multiple photos of the flight attendant and posted them on Twitter with the caption: "Hey @United, why are you breaking the law? Masks are required on all flights out of Canada. Your flight attendant isn’t wearing one! This is UA3737 in Ottawa right now."

Attaran attempted to get the flight attendant in trouble by tagging the official Twitter account for United Airlines.

United Airlines responded on Twitter, "Hi Amir, thanks for bringing this to our attention. We've informed the appropriate teams for further review."

Plus, Attaran tagged the official Twitter accounts for the Royal Canadian Mounted Police, Canada's transportation department, the Air Passenger Rights organization, as well as Canadian news outlets Global News, Canadian Broadcasting Corporation, and Globe and Mail.

\u201cHey @United, why are you breaking the law? Masks are required on all flights out of Canada. Your flight attendant isn\u2019t wearing one! This is UA3737 in Ottawa right now. @rcmpgrcpolice @Transport_gc @AirPassRightsCA @CBCPolitics @globeandmail @globalnews\u201d

— Amir Attaran (@Amir Attaran) 1655563360

Attaran spoke with the flight attendant after he mask-shamed her on his Twitter account.

"In Chicago now. Had a friendly chat with the flight attendant, and found she is blameless because @United misinforms its crew," Attaran tweeted. "WTF, United? Look here: on flights leaving Canada, masks are mandatory the 'entire travel journey.' FOLLOW THE LAW!"

The Canadian professor then called for United Airlines to be banned from operating in Canada because of the mask infraction.

"United should be forbidden flying to Canada—immediately. Our country, our rules," Attaran wrote in a post that tagged Omar Alghabra – Canada's Minister of Transport. "Even the supervisor I talked with in Chicago didn’t understand Canadian rules apply to flights departing Canada."

Attaran then lashed out at Americans, "Don't like Canada’s laws? Then keep your American companies in your own country. Our country, our rules. That’s why your COVID death rate is triple ours, a**holes."

He added, "Canada is not the USA, you f***ers."

The professor then called Republicans a "death cult," and seethed, "See Americans, you get crazy mad about COVID safety and attack science—and then you die. You drank the GOP Kool Aid and it’s mass suicide, basically. We in Canada did a lot better. So when you pout and cry about our rules—well, it’s kind of cute. Ratio that, motherf***ers."

"Oh, and if you Republican Reptiles dislike Canada’s COVID safety laws, you’ll TOTALLY HATE our gun safety laws—if you’re not already shot and dead," he feverishly ranted. "Cuz Yankees murder their own far more than Canadians. Even kids. It’s awful. I’m so glad I emigrated from California to Canada."

For hours, Attaran raged on Twitter as he battled anyone who criticized him for trying to mask-shame the flight attendant.

Attaran even blustered about former President Donald Trump's sex life and genitalia.

Twitter reactions to Attaran mask-shaming the flight attendant frustrated the Canadian professor.

BlazeTV personality @ElijahSchaffer: "A grown adult posted this."

Gov. Ron DeSantis spokesperson Christina Pushaw: "Leave her alone. This is beyond creepy. A professor taking photos of a young worker to shame her. Maybe don’t fly if you can’t handle seeing someone's face."

Journalist Yashar Ali: "Do you know what kind of hell flight attendants have been through during this pandemic? Dealing with harassment and bullying nonstop? And you post this poor woman’s photo and target her? And then admit later she didn’t even know?"

Art dealer Eli Klein: "Posting photos of someone publicly to report a mask breach and trying to get her fired/disciplined is unacceptable. Covid has really brought out the worst in people. Shame on you."

Lawyer Preston Byrne: "More evidence for the proposition that no profession has lost more professional standing as a result of social media than law professors."

Podcast host Hans Mahncke: "As @elonmusk might say, at their heart, mask mandates are divisive, exclusionary, and hateful. They basically give mean people a shield to be mean and cruel, armored in false virtue."

Conservative activist Ned Ryun: "And vaxxed 4x, 3x boosted and triple masked and you should be totally bulletproof. . . Against a virus with over 99% survival rate. Make sure to travel with a binkie and support animal next time. It will lessen the trauma maybe?"

Evolutionary behavioral scientist Gad Saad: "Every single time that this guy's tweets have come across my feed, I'm reminded that he is an execrable cretin. He was dancing in pure orgiastic happiness when he found out that @jordanbpeterson was gravely ill. What could lead a person to be so consistently mean-spirited?"

Commentator Michael Malice: "I didn't notice until now that professor Karen literally called in the cops on a black woman, and is blaming Trump fans for being reminded that he is absolute scum."

Columnist Derek Hunter: "Liberal attacking black woman in the hope that she get fired. #Typical#Progressive."

YouTuber Kelly Lamb: "Thanks Hall Monitor Attaran! You probably literally saved thousands of lives by reporting this to the correct authorities. A brave & truly selfless act."

A Twitter user remarked: "I’ll never understand the mentality of people who gleefully try to destroy other people’s lives just to gain a few minor but imaginary 'social credits.' Is there a more thirsty and sniveling personality type out there?"

Last year, Attaran was suspended from Twitter for attacking Prime Minister Justin Trudeau for not rolling out COVID-19 vaccines for children fast enough to his liking.