"Nobody knows what's happening," local videographer Jason Iggleden, who runs the Drone Shark App social media accounts, told Yahoo News Australia. "They didn't even know there was a shark there. But you can see one guy, he does see the shark."
The surfer can be seen pulling his legs back up onto his board the moment he realises what's underneath him, while Jason's partner Angie is close by with a GoPro and able to reassure him.
"My partner said, 'don't worry, don't worry, it's a grey nurse," Jason said. "But he is about the only one that did see it. The rest are just unaware. They're always unaware, they just don't really see it because the drone vision is way clearer than what you can see from your surfboard."
Nelly the local shark
For Jason, who comes out with his drone nearly every day, Saturday's experience at Sydney's famous Bondi Beach was like catching up with an old friend. "This particular shark, its name is Nelly and its been around the area for at least five years that I'm aware of," he explained.
But how can you tell one shark from the next? That would be Nelly's curved spine, believed to be a result of scoliosis, which may have resulted in its slightly smaller body.
According to Jason, Nelly has remained at about 1.7 metres in length for the five years he's known it. "I'm assuming it hasn't grown much because its food source is probably a little different to the normal grey nurse because of the deformity. It probably doesn't eat as much as the other grey nurses because I've seen them up to around 2.5 metres," he said.
Jason went on to explain there are around 10 grey nurse sharks that hang around the rocks off the cliff at Bondi, in deeper waters. "They don't always venture into shore but I have seen, when the salmon fish are really prominent, like 10 on the beach at once," he said. "And if it is a nice flat day, they will venture, especially if there are no waves. I've seen them literally two feet away from sand."
No need for alarm
Fortunately for beachgoers though, despite their large bodies, pointed snout and many rows of visible teeth, grey nurse sharks are "generally a slow-moving species that is not considered dangerous to people," according to the Australian Museum.
"In five years of filming those grey nurse sharks, I've never really seen any aggressive movements towards humans," Jason said. "They do come in for a little look sometimes but then right at the last minute they just shy away but never in an aggressive manner. They're always cruisey. But they can move really fast if they want."
'Just saying g'day'
The video — which also includes footage from Angie's GoPro — has since been viewed more than 25,000 times. "Crazy underwater shot of shark next to surfer's leg," Jason wrote online. "Don't worry it's only Nelly's adventures yesterday at Bondi, scaring surfers, swimmers and basically just saying g'day mate."
And if you still have reservations about ocean swimming, this might be the footage to put you at ease. "You can almost touch Nelly," Jason can be heard saying in the clip as the shark glides close to those in the water. "You can see Nelly has just got no interest in humans whatsoever."
Love Australia's weird and wonderful environment? Get our new weekly newsletter showcasing the week's best stories.