A group of tourists were seen scrambling on to a boat as six sharks stalked the shallow water around them.
The boats were anchored near Orange Beach, a popular island off the coast of Alabama, when they were approached by a group of hammerheads, which have been known to attack humans.
One of the passengers Meredith Perry caught the terrifying encounter on her phone and shared the footage on Facebook.
In the heart-stopping clip, a man just manages to lift himself out of the water as the predators tail closely behind him.
He manages to just get to the swim deck as people in nearby boats capture the rare moment on their phones.
The hammerheads continue to stalk the shallow waters around Robinson island momentarily, before one thrashes and races off to sea.
A group of excited youngsters can be heard chatting to their parents after the scary encounter.
Meredith's fiance, Paul Hubble, told local media WLBT that there were as many as eight sharks swimming in bteween the boats.
He shared: "All of a sudden we started hearing people say 'shark, shark' and then everybody getting on the boat.
"People thought they were fixing to get eaten alive or something. We got kids, and I walked around the boat and noticed they were hammerheads.
"You could tell they were feeding on something and doing their thing.
"Everybody was climbing all over the boats and stuff. It was very dramatic to see for sure in probably two feet of water, if that."
Meredith also took a video of her fiance staying in the water.
And Paul added: "If I had known my fiancee was filming me, I would have knelt down and let them slurk around.
"I've never seen that, every weekend for years I've come out and I've never seen sharks come up like that."
He said the sharks stayed around the boats for about 10 minutes and swam out to deeper water, reports the Daily Star.
National Geographic reported that most hammerhead species are considered "harmless to humans" and "very few attacks have been recorded".
Earlier this week, in a far less pleasant encounter, the body parts of a Russian man were discovered inside the belly of a great white off the coast of Egypt.
The body parts of a Russian man who was eaten alive by a shark in Egypt have been recovered from inside the beast's belly.
In footage too gruesome to publish, the man, identified as 23-year-old Vladimir Popov, is seen duelling with the fearsome beast before losing his battle.
The shark was caught and clubbed to death on the beach before specialists dissected it and found Vladimir's remains in its intestines, local outlet Al Arabiya reported.
The Egyptian Ministry of Environment said in a statement that "the men of the Red Sea Reserves concluded that" a tiger shark was the one that attacked a beachgoer, which led to his death.
Vladimir had gone swimming off one of Egypt’s Red Sea resorts when the beast emerged in the waters near the city of Hurghada and grabbed him.
The nearly minute-long video shows Vladimir being suddenly pulled down into the water. He briefly resurfaces and desperately tries to fight off the shark.
The 23-year-old's body can be seen bobbing up and down in the water, as his legs spin in the air.
Vladimir screams "Papa" and cries out loudly as the shark repeatedly circles and comes back in to attack. But in seconds the water around him goes red.
