You wade through the water as you slowly make your way closer to the cave; your curiosity had overpowered your fear. Finally, you're in the cave and all you can see is black. You wave your hand in front of your face- nothing. Panic starts to overcome you, and you think about turning around when suddenly a circular light the size of your palm appears a couple of feet away from you. 

You're frozen with fear as it comes closer, flashing a few times. It comes into vision and you realize how it was flashing.

It's an angler fish. The flashing continues, and you realize its morse code. You decode it, and discover it means: "don't move."