The St Petersburg City Council voted last month to ban plastic straws by 2020, beginning with a grace period in 2019 in which customers must specifically request plastic straws at city businesses.
Biandudi watched as an insult-ridden, profanity-laced argument about straws escalated between the customer, a tall white man, and the employee, a young black woman. That's when she pulled out her phone.
"I said, this is getting a little heated here," Biandudi told the Post. "I better get my camera ready in case somebody needs to know what happened."
As soon as Biandudi began recording, the argument turned physical.
In her video, the man can be seen leaning across the counter and grabbing the cashier until she lurches forward. For a moment, the employee seems to stumble, then regains her balance and begins flinging punches at the man.
Other people can be heard shouting "Let her go" and "Stop!" After about 15 seconds, another McDonald's employee walks around the end of the counter and pulls the customer back until he lets go of the woman.
The employee continues shouting as she is escorted away by a co-worker, while a man in a McDonald's uniform steps up to the counter and addresses the belligerent customer. Moments after the altercation, the employee returns to the counter area to look for her phone.
The customer points at her and shouts, ostensibly to someone he thinks is a manager, "Sir, I want her a-- fired!"
This prompts the woman to retort, "No, you're going to jail!" The man then screams more profanities at her.
At last, a McDonald's employee tells the customer: "Sir, get outta here."
Biandudi said she stopped recording after that and went outside to get her daughter in the parking lot. She soon returned, knowing someone behind the counter had called police, and stayed in case officers wanted to review the video she had taken.
By then, the belligerent customer was verbally accosting the manager - a part of the incident she didn't capture on camera, she said.
"He came back in the store and went behind the counter and got in the manager's face," Biandudi said. "And another employee, a bigger guy, he actually grabbed the guy and put him outside the door and locked the door."
By the time police arrived, the man had left the McDonald's, she said.
Biandudi said she spoke with police and later shared the video with family members. Her son and daughter asked whether they could post the video online, and Biandudi agreed, hoping someone might be able to identify the customer.
"I was just disappointed the guy got away," Biandudi said. "It was the right thing to do. Some people say the customer's always right. (The cashier was) a young girl. I wanted her to keep her job. I wanted the guy to be caught."
The video garnered millions of views after Biandudi's children posted it on Facebook and after it was shared by the Atlanta Black Star, an online magazine.
Later, police arrested Daniel Willis Taylor, a 40-year-old transient man, according to an arrest affidavit from the St Petersburg Police Department. There were no weapons found on him, and there were indications that he was under the influence of alcohol, police said.
Taylor was charged with two counts of simple battery and was ordered to stay away from the restaurant and avoid contact with the employee. He is awaiting trial in the Pinellas County Jail, records show.
Arrest records also indicate that there was further violence not captured on video.
"The victim was kicked in the stomach by the defendant, and was complaining of pain," police stated in an affidavit. "The defendant was being escorted out of the business by management due to him battering another employee, and causing a disturbance. The defendant kicked the victim in the stomach while she was standing near the exit door."
A McDonald's representative did not respond to specific questions sent by email - including what protocol employees should follow if a customer turns violent - but said instead the company was "fully cooperating" with police.
"Our highest priority is always the safety and well-being of our employees and customers at our restaurants," McDonald's said in a statement.