Brock Lesnar is the most dominant athlete in both WWE and UFC history, but it was a battle within himself that nearly brought his career, and life, to a screeching halt. After accomplishing everything he needed to over a two year period in WWE. Lesnar left to try his hand at the NFL, which didn't go so well. From there, he tried his hand at UFC, which initially didn't go so well either. He lost his first fight in the organisation to Frank Mir, but won his second against Heath Herring and his third against Randy Couture to win the UFC Heavyweight Championship. In 2009, it was revealed that Lesnar was suffering from diverticulitis - a potentially fatal digestive disease of the bowel. As a result of this disease, Lesnar suffered a perforation in his abdomen which caused pain, abscesses and stretched his immune system to breaking point. Remarkably, he recovered from this, and went on unify his Heavyweight title with Shane Carwin's. Unfortunately, he was no longer 100%. He lost his title to Cain Velasquez to a first round TKO. Not long after, he was once again struck down again with the disease, and when he recovered he lost his return fight to Alistair Overeem and promptly retired from the sport.
