Local novelty app-maker Riley Walz is on something of a tear, garnering local media attention from the Chronicle and others for the third time in almost as many weeks with a prank on Waymo vehicles.

A few weeks back we brought your attention to Find My Parking Cops, a very short-lived app created by 23-year-old local engineer Riley Walz that drew on publicly available parking-ticket data to display the daily movements of the SFMTA's parking enforcement team. (It has since been shut down by the SFMTA.) Prior to that, we talked about LooksMapping, a fairly silly app that ranked the average hotness of restaurant patrons in SF, as well as New York and LA.

Now, Walz is grabbing headlines again this week with a prank on Waymo, which he documented on social media, and which was subsequently picked up by the Chronicle. Walz gathered 50 people to head to "San Francisco's longest dead-end street" — which appears to be near the Presidio? It's unclear. The group then all ordered Waymos to pick them up, and then no-showed for the rides, for which they were each charged $5.

The robocars were then all left to figure out how to get out of there. And, as Walz notes, "Everyone was giddy, and when another car showed up there were cheers."

The prank actually took place in July, and perhaps at the risk of being banned from Waymo — or, as one commenter suggested, getting taken out by Google's secret private army — Walz is going public with it and he praises how Waymo dealt with the mess.

"Waymo handled this well," Walz says. "I assume this isn't much different than if a big concert had just ended. Eventually, they disabled all rides within a 2 block vicinity until the morning."

Of course, we don't want anyone else getting any big ideas and doing something like this in a malicious way — and who but a couple dozen overly caffeinated, nerdy 20-somethings would even be likely to pull this off?

Google/Alphabet has not offered any comment.