LIKE much that moves in twitter-mad Saudi Arabia these days, it started with a single message. A lady in Dammam, the hub of the oil industry on the kingdom’s Gulf coast, tweeted a complaint from a local shopping mall. Agents of the Committee for the Promotion of Virtue and Prevention of Vice, she said, were causing an unpleasant scene. The government-salaried vigilantes, a bearded auxiliary police force familiarly known to Saudis as the Hayaa, which is supposed to enforce public morality, had marched officiously into an educational exhibition featuring plaster models of dinosaurs, turned off the lights and ordered everyone out, frightening children and alarming parents.

It was unclear precisely why the religious police objected to the display, which had been featured at shopping centres across the Gulf for decades. Malls are one of the few public spaces where Saudis mix socially, and so often draw the Hayaa’s attentions.

Gone, however, are the days when its agents can go about their business unchallenged. Within minutes of the incident, a new Arabic Twitter hashtag, @Dammam-Hayaa-Closes-Dinosaur-Show, was generating scores of theories about their motives. Perhaps, suggested one, there was a danger that citizens might start worshipping dinosaur statues instead of God. Maybe it is just a temporary measure, said another, until the Hayaa can separate male and female dinosaurs and put them in separate rooms. Surely, declared a third, one of the female dinosaurs had been caught in public without a male guardian. A fourth announced a police alert for Barney the Dinosaur, while another said people should wait to judge the incident until they knew what the dinosaurs were wearing.

Some tweets cast the episode in political terms. “Why close the show?” asked one. “It’s not as if we don’t see dinosaurs in newspapers and on TV in the government every day.” “They should go after the dinosaurs who sit on chairs,” suggested another, seconded by a tweep who suggested that dinosaurs in gilt-trimmed cloaks, the garment of choice for senior sheikhs, would be a better target.

Several contributors injected bawdy innuendo. Noting that one of the displays showed one dinosaur riding on the back of another, one message declared that this was obviously sexually suggestive and possibly could be categorised as a Westernising influence. “I confess,” declared one penitent, “I saw a naked dinosaur thigh and felt aroused.” Another tweet provided this helpful tip to the suspicious Hayaa: “No, no, that long thing is a tail!”

Most of the messages singled out the religious police for ridicule. “They worried that people would find the dinosaurs more highly evolved than themselves,” explained one. “Hello Stone Age,” wrote another. “We have some of your people—can you please come and collect them?”