Tesla lovers can be forgiven their hallucinations for seeing a “ghost” Model S on California roads last week that didn’t look like any Model S they know of.

The close encounter with the ghost Model S, appropriately sporting a matte black paint job, was widely reported in Tesla owners’ forums. Photos of the UTO (Unidentified Tesla Object) were even posted.

After sifting through the sighting reports and the conjecture, Tesla experts conclude this previously unknown version of the Model S is a “Model S Refresh.”

This latest Tesla mystery began when a Tesla owner driving his electric vehicle (EV) near Tesla's Fremont headquarters sighted a mysterious car he suspected might be a new version of the Model S he’d never seen before. This man noticed "bigger" headlights on this model, as well as tail lights not the same as those on the current Tesla Model S.

A post at Tesla Motors Club said this man who called himself Vinc saw a matte black Tesla travelling on the opposite road. There was a similar looking refreshed Model S right behind it.

He said the wrapping of the car in front caught his attention.

“It was very mismatched, with some panels glossier than others,” wrote Vinc in his post.

He first thought it was “one sloppy wrapping job.” He also found something odd about the shape of the car itself. While the EV had passed him, he still saw the rear lights were different from that of a usual Model S. They looked bigger, he wrote.

And, no, this EV isn’t at all a Model Y crossover SUV despite its conspicuously raised rear-end.

Tesla Model S open hood Tesla cars have the quality and utility which makes its high resale value reasonable. Pictured: A Tesla Model S car is displayed at a Tesla showroom on November 5, 2013 in Palo Alto, California. Tesla will report third quarter earnings today after the closing bell. Photo: Getty Images/Justin Sullivan

A shared consensus among some Tesla watchers after going through the posts is these two cars are refreshed versions of the Model S, whose sales are flagging. Tesla pundits say sales of the S and X have been falling sharply in the wake of widespread Model 3 availability.

A refreshed Model S might revitalize customer interest in the aging Model S (which was first produced in 2012). So, is a Model S upgrade in the works? The answer is, most likely.