In the past few years "concussion" has become a buzzword in the world of professional sports. The world of Sports Entertainment is no exception with the WWE making headlines after initiating, and adhering to, a strict Concussion Policy that includes annual baseline tests and tests administered shortly after a Superstar shows symptoms of a concussion. If he or she fails they cannot return to action until they pass a future test and are cleared. Although symptoms and levels of damage vary, a concussion is classified as a traumatic brain injury caused by a sudden blow to the head or certain movements that send the brain and head quickly moving back and forth. This can alter the way the brain functions and can manifest in a variety of ways: vision issues, confusion, and memory loss being the most common. These effects, and worse, are usually short lived but can sometimes linger for months or longer in extreme cases. The world is finally starting to pay attention to how concussions, especially multiple concussions, can affect a brain over the long term. In the past, athletes who had their "bell rung" would shrug off their side effects from a concussion and continue to perform, often not remembering the events before, during and after the hit. While WWE has made many changes to try and curb dangerous concussions it is impossible to eliminate them all. Equally impossible is to try counting the amount of true concussions professional wrestlers have incurred over the years, as years of hard bumps, unprotected chair shots, and tables, ladders, and kendo sticks have all played a part in damaging brains, one hit at a time. The following are 10 of the most famous concussions in wrestling, some remembered for the amazing and dangerous acts around them and some remembered for the unfortunate consequences that followed.