It's been well over a year now since we were first introduced to the all-new 2020 Chevrolet Corvette C8 - GM's first rear-mid-engine sports car since the Pontiac Fiero of the 1980s - but the C8 lineup still has plenty of surprises in store. For instance, there's the hotly anticipated C8 Z06, which is expected to draw its power from a road-going version of the Corvette Racing team's high-revving dual-cam V8, and the C8 ZR1, which is rumored to be getting a super-powerful hybrid powertrain centered on the same high-revving 5.5-liter engine.

But we don't think it was either of these cars that was recently caught testing in the mountains in California.

The video above shows a trio of Corvettes - two draped in shape-obscuring black cladding, and one unclad yellow C8 Stingray - as they drive a scenic California mountain pass. The video is described as "a teaser," with additional clips showing more spirited driving expected to be uploaded in the near future

The CorvetteForum user who uploaded the video also shared a photo of three black-clad Corvette test mules waiting at a traffic light with the same yellow Stingray, allowing us to get a closer look at them.

The test mules all appear to be running wider-than-normal bodywork, presumably to accommodate deeper wheels with a bigger section width than what the regular Stingray comes equipped with. Notably, though, all three feature exhaust tips that are split up into two pairs, one on either side of the car. The Z06, by contrast, is expected to sport a pair of tips located in the center of the car.

Considering that, there's a good possibility that these test mules are actually being used to develop the rumored Corvette "E-Ray" - an anticipated hybrid-electric model that pairs the standard 6.2-liter LT2 V8 with an electric drive unit on the front axle. The first-ever Corvette hybrid is expected to launch some time in 2022 as a 2023 model.