These snakes are one of the most common types of sea snakes – which is a little disconcerting as they are also one of the most venomous! ... At first glance, the blue-ringed octopus seems completely harmless. The ocean is full of deep and full of terrifying creatures. These deep sea predators are actually harmless to humans as they hunt squid and smaller fish. The ocean is full of amazing creatures, from deep-sea vents thousands of feet beneath the water's surface to sunlit coral reefs. These fish can be observed between 600 and 6500 feet deep where temperature can drop drastically and pressure can be quite extreme. (Be ware: nightmares within!) Scientists estimate that their venom is between 4 and 8 times more deadly than that of the cobra, and they are known to be one of the most aggressive of all the sea snakes. It's vibrantly colored, smaller than a candy bar, and doesn't look like it could hurt a fly. But when provoked, they can deliver a bite that can kill you. So, here we are listing the top 20 most terrifying deep-sea creatures. Here is another one, Vampire Squid has the largest eyes of all animals in the world. ... Vampyroteuthis infernalis is harmless. Here are the most fascinating and bizarre marine creatures in the ocean, from the toothy bobbit worm, to the unfortunate-looking blobfish. One of the deadliest sea creatures in the world can be found in the Philippines- the blue-ringed octopus. Before you splash in the sea this summer, it'll behoove you to bone up on the deadly and dangerous sea creatures potentially lurking in the depths. It is one of the terrifying deep-sea creatures. They are very tiny and attractive so one can easily think they’re harmless. Frilled Shark 2.Beaked Sea Snake. Deep-Sea Creatures 1. It has intensely red eyes and cloak-like webbing. These sea creatures are of yet another species which may be found in a sci-fi movie.