Pop superstar Lady Gaga suffered a concussion Sunday when one of her dancers mistakenly hit her over the head with a pole used as a prop for her "Born This Way Ball" tour.  The singer was performing "Judas" in Auckland, New Zealand when a dancer mistimed his removal of a metal pole and Gaga was hit in the head.  The singer rubbed her head, then walked offstage briefly before returning to finish her show, performing another 16 songs before gettiong checked out by medical staff.  Check out the video clip of the incident below.