Bagpipers, zombies, kittens, flu shots, ice cream, Justin Bieber — does it ever end?

The marketing departments at ride-hailing rivals Uber Technologies Inc. and Lyft Inc. are locked in a seemingly endless cycle of one-upsmanship, pumping out one limited-time gimmick after another in their quest to generate cheery headlines and attract new customers.

Lyft fired the latest salvo Wednesday by announcing “Ghost Mode,’’ a button in its smartphone app that will allow riders to request a pickup in an “Ecto-1,’’ the vintage Cadillac hearse tricked out with phantom-fighting equipment featured in the Ghostbusters movies. (There’s a reboot film coming out next month, in case you haven’t heard.)

In addition to several real Cadillacs, Lyft has wrapped a number of Toyota Highlanders with Ghostbusters graphics to help meet demand.

“Ghost Mode’’ will available in the Boston area on Friday and Saturday between 10 a.m. and 8 p.m., according to the company. The promo is also running in New York City, San Francisco, Los Angeles, and Washington, D.C.

Those who manage to snag a ride in an Ecto-1 will also have a chance to take home “Ecto Coolers’’ juice from Hi-C and Ghostbusters-themed Twinkies by Hostess (each of which sounds about as appetizing as the green slime from the 1980s movies, but to each their own). Two grand prize winners get tickets to the July premiere of the new Ghostbusters flick in Los Angeles.

“Ghost Mode’’ is similar to Lyft’s earlier “McFly Mode,’’ which allowed customers to summon a DeLorean on Oct. 21, 2015, the date to which the heroes of “Back to the Future Part II’’ travel.

Meanwhile, Bloomberg News reported this week that Lyft has warned investors it expects ridership to stay flat or even decline slightly in June, thanks to the company’s withdrawal from the Austin, Texas, market and because college students are returning home for the summer. Still, in May, the company set a record for rides provided.

Dan Adams can be reached at daniel.adams@globe.com. Follow him on Twitter @Dan_Adams86.