6. Umbrella Man
There's two aspects to this theory, one plausible and one simply mad. The infamous "Umbrella Man" was actually identified about 15 years later as Louis Steven Witt, who carried the black umbrella on this sunny day as a way to heckle Kennedy in Dealey Plaza for his father's support of Neville Chamberlain, the black umbrella of course being his trademark accessory. Some people, however, just never give up. There are those who believe that while there was no actual second shooter, instead Witt was on the ground waving his black umbrella from east to west as a signal to Lee Harvey Oswald to take the shot. Then, we come to the completely mad theory, again one that can be explained by the back brace as well as the autopsy results and a small dosage of common sense, that Witt had fired a poisoned dart (yes, A POISONED DART) at Kennedy to immobilize him in the barrage of gunfire that emerged from the book depository, explaining why he froze in the moments before the fatal shot. Or, you know, it could have been that he was shot before that. No, let's go with poisoned dart because that's much easier to believe.