Sure, this is mostly fans having fun, but there’s a reason why tasseography has survived for centuries, and why many people in the Bay Area, and Toronto, are wearing sticky, unwashed jerseys today. Athletes on both teams are likely running through their pre-game rituals, too.

Quartz’s Oliver Staley, a former collegiate distance runner and committed rational thinker, tells me he gets it. Establishing some seemingly superstitious routine has its own logic. “If you do the same thing every time before you compete, then you don’t have to worry about whether you’re doing the right things or not, and it can be calming,” he says. In other words, the preparation work reduces the risk of decision fatigue.

Plus, that confidence and psychological certainty can pay off, he suspects. He points to Wade Boggs, the former Red Sox and Yankees player who famously ate chicken before every baseball game for 18 years. “It probably didn’t make him a better hitter, but since he believed it did, it probably did,” says Staley. Boggs is now in baseball’s Hall of Fame.

For the record, the clouds that look like dinosaur claw marks are “Altocumulus undulatus radiatus,” according to Gavin Pretor-Pinney, founder of the Cloud Appreciation Society. Its “wave-like ridges form as a result of shearing winds at the cloud level setting up rising and dipping undulations in the air,” he told Quartz in an email.

Pretor-Pinney, also the author of The Cloudspotters Guide: The Science, History and Culture of Clouds, is no stranger to the curious, age-old habit of forecasting earthbound events by reading vapor patterns. “Cloud shapes were often considered as indicative of the mood, not just of the weather, but also of the divine,” he says, so unusual shapes would be seen as good or bad omens before major battles of the past. “It seems quite appropriate, then, that this is a sure sign of what is in store for the NBA game tonight.”

📬 Sign up for the Daily Brief

Our free, fast, and fun briefing on the global economy, delivered every weekday morning.