This Panamera needs some surgery to take care of the tumor on its back.

Automakers do weird things to vehicles during testing, but this bumpy Panamera is one of the odder recent examples. An eagle-eyed Motor1 reader used our Tip Us function to send us these three bizarre photos from Germany. According to our tipster, he spotted this car “between the cities Weinsberg and Heilbronn,” which placed it about half an hour up the road from Porsche’s home base in Zuffenhausen. He wanted to know if we had “an idea about the bubble in the roof?"

While we don’t know for certain, Motor1’s editorial team thinks there’s one decent possibility and another dark horse option. We believe that the more likely scenario is that this Panamera is a test mule for the recently spied Cayenne Coupe, and the bump is a way to adjust the roof temporarily. There’s a precedent for automaker’s fitting weird top appendages while developing a model, too. As further possible evidence, the Cayenne Coupe was underneath a jacked up black Panamera – kind of like this one.

The still plausible, though less likely, possibility is that this is a test mule for the long-wheelbase Panamera. In that case, the roof bubble would be a temporary extension or a way to test extra headroom. Product director Dr. Gernot Dollner already confirms the bigger sedan’s existence, and the changes would increase interior room. However, long-wheelbase test cars don’t usually have bulges on top, so we’re not sure why Porsche would need to add one here.

For now, this vehicle is a fascinating mystery. It tells us Porsche has something interesting in development but doesn’t offer any clues about the vehicle’s identity.

If you ever spot an especially weird car on the road, feel free to send the photos to us by clicking the Tip Us button on the top right of the page. We would love to see them, and we might even feature them on Motor1.

Gallery: Porsche Panamera roof bubble spy

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