The Crocodile Hunter's Final Days, on Camera

Jan. 19, 2007— -- Nineteen hours before his death, Steve Irwin was wrangling poisonous sea snakes.

Why? To milk them for life-saving venom, as part of what would turn out to be the last documentary he filmed, called "Ocean's Deadliest," which airs Sunday night on Discovery's "Animal Planet" channel.

The video of Irwin's tug-of-war with the sea snakes provides the last surviving images of Irwin, because the video from the next day -- of the famed "The Crocodile Hunter" being killed by a sting ray -- has been destroyed, at the request of his wife.

"Terri felt that it has no educational value for anybody," says John Stainton, Irwin's longtime filmmaking partner and 'best mate,' as they say in Australia. When asked if he had seen the video, Stainton replied, "I had to watch it. It was incredibly sad and incredibly horrible." what does he miss the most about Irwin? "Just talking to him every day. You know, we probably started talking on the phone every day at 5:30 in the morning."

"Ocean's Deadliest" takes a look at the world's most dangerous sea creatures. When Stainton and Irwin started filming it, sting rays were not even on the list. And they do not play a prominent role in the final cut airing Sunday. "Not even now, I don't find them dangerous. It's like any animal. It's doesn't matter…a dog could kill a child. It was a freak accident. We were in the wrong place at the wrong time."

Jellyfish were on the filming schedule last Sept. 4th, the day Irwin was killed. But out on the Great Barrier Reef, there were no jellyfish to be found. To pass the time, Irwin decided to go for a quick dive with his crew and do a bit of filming for his daughter's TV show. Stainton stayed on board "Croc One," as did Irwin's co-host for this documentary, famed oceanographer Jacques Cousteau's grandson Philippe Cousteau.

"We got the call and it all changed in an instant," Cousteau recalls. "He was just a few hundred yards away from the boat, and we didn't know what was going on." There was nothing anyone could do. By sheer bad fortune, the startled sting ray had pierced Irwin's heart. He stopped breathing almost immediately.