weird .part files in download folder I'm using Mac OS X 10.7.3. 
It happens sometimes that there are .part files in my download folder, with the length of 8 characters and 0kB file-size. 

Could this be a virus?

Examples I see are like these 2: 3dOsdT+d.part and utYYNFFo.part
It's not a virus. The ".part" files are partially downloaded files seen during a download or seen later if a download has been interrupted.

Once a download completes successfully, the ".part" file will be renamed to the actual name of the downloaded file. Any (older) ".part" file can be deleted and the deletion would not cause any issues.