Well...let's see...
Guy is circled by 4 or 5, 10' long aggressive sharks, ....
Guy dangles foot in water for sharks to bite....
Guy gets bit by said shark...
Well if calling this guy stupid offends you...lets just call him not smart....
I would call it an unfortunate accident if he didn't know...or actually see the shark before it bit him...but according to the witness they were both fully aware of the sharks presence...and he still chose to dangle his foot over the side...
