Many of us will still remember the infamous iPhone 4 prototype that was left in a bar before being sold to a website. This led to the images of the device spreading around the web like wild fire, and something similar happened last year with another iPhone prototype being mislaid that led to the involvement of the San Francisco police. Today we have news of another mystery prototype phone being found that has prompted a guessing game.

The guys over at Droid Life are reporting about the device in an article, and before you get excited it’s not the iPhone 5. The mystery handset was again found in San Francisco and this time in a restaurant, and is marked up with a number of serial numbers that the site has blurred out.

Round at the back of the device is semi-see through and is reminiscent of HTC Droid Incredible 2 from the front. There is a micro USB charging dock that is located in the same place, along with the camera, but the volume controls are in a different position. Where the volume rocker was placed on the Incredible 2 there is some sort of other control now.

All that is missing are any logos, and the device seemingly has been wiped remotely with the screen showing ‘No System Software’. Also the handset doesn’t feature a removable battery unit, which is something the HTC One series has recently adopted while the Incredible 2 unit was removable.

The prototype certainly does remind you of an HTC handset, but it is strange why anyone would still be using an Incredible 2 prototype considering the device is a year old now. There will obviously be someone either in trouble or embarrassed by the loss. Hit the link above for more images of the mystery handset.