YouTube user SeabearVideo has posted a video which opens with the sub-title “Possible Great White Shark Tries to Attack Surfer” and then goes on to feature some surf footage during which a dark shape can be seen swimming alongside one surfer catching a wave and then underneath another surfer paddling in the opposite direction.

The footage was shot near San Diego, according to the video description, so the presence of a white shark in that area this time of year certainly wouldn’t be unheard of. However, the shadowy shape is fairly indiscernible in the video. So, is this just a shark or other marine animal out for a swim or could it possibly be a white shark attempting to attack one of the surfers? If you’ve got an opinion on it, sound off in the comments.