Braxton Rocha, 27, was spearfishing 60 m offshore along a remote stretch of the Big Island coastline. After checking an underwater cave, he caught a flash of stripes in the corner of his eye and was face-to-face with the largest tiger shark he had ever seen. "Once she locked on my leg - I cocked back, I punched her in the nose." "She let go and swam away." Rocha said that he swam as hard as he could against a strong current to get to shore.... "I'm just happy to be alive, happy to have my leg," Rocha said.