A video of a man fighting off a great white shark in Sydney Harbour is too scary to be true, critics say.
The video, uploaded by "Terry Tufferson", shows a man with a GoPro camera jumping into the harbour (from quite a height, it must be said) and coming face to face with the shark.
"Shark! Shark!" His friend calls from above. "Right behind you!"
Through the lens we see the great white swimming towards and around the man. At this point, some critics have pointed out, patchy editing begins to show.
Despite being metres from shore, the swimmer takes an awfully long time to move.
The whole clip is only 1.38, and ends with the subject climbing to safety, turning the camera, and saying, "holy s**t".
The clip has caused controversy online, with commentators raising suspicions about the fishy footage, saying it's possibly a marketing ploy from GoPro.
YouTube posters highlighted that at the 0:59 mark the shark flashes briefly in the centre of the screen and then suddenly shifts to the left of the frame.
Gizmodo's Campbell Simpson also suspected it was a fake, The Huffington Post reported.
"Big sharks in the harbour area are rare, and if I jumped from a rock cliff into the water and saw that staring back at me, I'd be swimming non-stop for terra firma, not stopping occasionally for the shark to conveniently swim past the camera," he said.
The clip, uploaded on June 11, has had more than 1.5 million views.