This is incredible footage. But seriously, I really hope this guy stopped filming and sought shelter!
This is exactly why you're supposed to leave the water at the first sign of an approaching storm:
According to scientific review of the film, the massive strike was something called a secondary strike. HowStuffWorks explains the phenomenon of a secondary lightning strike, saying, "It is very possible that a main strike can be followed by 30 or 40 secondary strikes. Depending on the time delay between strikes, we may see what looks like one long-duration main strike, or a main strike followed by other flashes along the path of the main strike." No matter what it's technically called, this bolt of lightning is fascinating!