A man in Sydney, Australia was spotted swimming right next to a shark without him even realising it.
The footage was caught on camera by the Drone Shark App at Bondi Beach. This app provides drone footage to surfers warning them of nearby sharks spotted in the area.
The App operators said that for a moment they were shocked at seeing the shark passing past the salmon in the area and following the swimmer, however, shortly afterwards it turned around and swam back out to sea.
They said that they had shouted a warning to swimmers though a megaphone that there were two sharks nearby.
In this case the shark happened to be a Grey Nurse species which is normally not aggressive and rarely attacks people.