It began with social-media posts claiming the head of the Women's Basij organization in Iran had announced that "women will soon be banned from eating ice cream in public places" and that "violators" will face stiff punishments.
As the claim spread on Twitter and Telegram, some openly criticized the "nonsensical" crackdown attributed to Minou Aslani, leader of the women’s branch of the Basij domestic security force.
Others said they knew of cases in which women had been warned about the lasciviousness of licking an ice cream cone in front of others.
One Iranian woman described on Twitter how she'd personally been warned by the authorities at a 1993 Tehran book fair not to eat ice cream in public. She said the reprimand seemed "ridiculous."
Others just poked fun at the alleged new ice cream ban.
"Please come for your daughter," one mocking post on Twitter said.
"Where is she?
At the police station.
What has she done?
She was eating ice cream in the street."
In fact, there is no officially published prohibition on ice cream licking in Iran.
But in a country where women already face so many social, political, and legal restrictions, claims about such a ban appeared real enough to cause alarm.
Those concerns prompted a public denial from Aslani, who dismissed the rumors as a plot by what she called the foreign "enemies" of Iran.
"We deny this. Of course, the enemy was so angry over the gathering [in support] of chastity during Hijab Week in the country that they designed this rumor in their think tanks and spread it," Aslani told a July 17 press conference in Tehran.
An Iranian man behind one of the first Twitter accounts that posted the claim told RFE/RL it was meant to be a joke.
@Golabberoot said he wasn’t surprised that some people took the joke seriously.
He says that’s because there are so many absurd restrictions against women in Iran that "irrelevant" bans have become "normal."
He also notes that Aslani, known for her hard-line views, has made many "strange comments" in the past.
According to Iran's official government news agency, IRNA, many Iranian social-media users believed the claims about an ice cream ban for women, while only a few saw through the false reports.
IRNA said the incident showed that the adoption of laws not approved by the people "leads to a degradation of the status of laws among the people and reduces their trust in the law."
"Therefore, it is imperative for legislators to push for laws that are acceptable to the people," IRNA said.
Women in Iran are required to cover their hair and body in public under a law calling for modest "Islamic" clothing.
Many women have been pushing back against the forced hijab rule by showing much of their hair under small or loose scarves, by wearing makeup, or by dressing in tight-fitting coats.
Women have also defied the hijab rule, which became mandatory after Iran's 1979 revolution, by simply removing their head scarves in public.
Other restrictions include discriminatory laws forbidding travel abroad by Iranian women without written permission from their fathers or husbands, and unequal rights in divorce and child custody cases.
Women are also banned from singing alone in public and from attending male sports events.
Some conservative religious officials, including Supreme Leader Ayatollah Ali Khamenei, have declared that it is a sin for a woman to ride a bicycle in public.
And hard-liners have been calling for tighter controls on how a woman can appear in public.
"The more women dress in an openly sexual way, the less we'll have social peace while facing a higher crime rate," Aslani told the state-supported Hijab Week rally in Tehran on July 11.