Answer: The dangers are decompression sickness arterial air embolism, and of course drowning. There are also effects of diving, such as nitrogen narcosis, that can contribute to the cause of these problems. And sea creatures like Great White Sharks, Lionfish, Sea snakes, Cone Snail, rays, The great barracuda, Flower Urchin, Stonefish, Blue Ringed Octopus. And more