When BASE jumper Brendan Weinstein took to the skies in a wingsuit over the eastern Sierra Nevada mountain range on Sunday, he had no idea he was being trailed.
It was only upon reviewing his camera footage a few days later, Weinstein told The Huffington Post by phone, that he spotted what he initially thought was another human thrill-seeker.
"I'm thinking, 'How the hell was there another wingsuiter on exit and they snuck up behind and magically exited right after me,'" he wrote in a Facebook post.
As it turned out, the object in hot pursuit was a peregrine falcon -- widely considered the world's fastest animal.
After entering a high-speed dive, the magnificent predator catches Weinstein in just seconds.
Weinstein told HuffPost that in his two years of BASE jumping and four years of skydiving, he's never seen anything like this.
"I think this is unheard of," he said.
Weinstein has several theories about why the falcon chased him.
"One is that maybe it thought it saw some dinner," he said, adding that when the bird got close enough, it was likely disappointed to find a meal far too large to take down.
Another possibility, Weinstein said, is that the falcon had a nest somewhere below the area from where he BASE jumped and was trying to defend young chicks.
Or perhaps the falcon -- a species that has been clocked at speeds topping 200 mph -- was just trying to show off.