Every so often the image flashes through Nicholas Grisaffi's mind.
The trigger can be a blond woman who looks like the one Grisaffi, a 61-year-old Laguna Beach man, and friend Rick Moore tried to help out of the ocean in Maui last month.
"That arm flashes at you," Grisaffi said.
Moore and Grisaffi, a Tustin elementary school teacher, were planning to spend a relaxing day at White Rock beach, an area known for its snorkeling, on the late afternoon of Aug. 14.
The two arrived in the parking lot but Moore, a pastor and Irvine high school teacher, couldn't find his underwater camera. He spent 10 minutes looking in the trunk of the car and in his bag, but couldn't find it.
Moore, 57, and Grisaffi reached the beach and noticed snorkelers near some rocks.
Then a scream pierced the air.
"It was horrific screaming, the kind you don't want to hear," Grisaffi said. "She had blood around her."