How dangerous are cobras?

Cobra bites are fatal in about 10% of human cases. it's because of their VENOM that acts as a defense mechanism and also a way by having their pray or food be caught.

Any of several highly venomous Elapids snakes that expand their neck ribs to form a hood. They are found in warm regions of Africa, Australia, and Asia. Cobras feed primarily on small vertebrates. The Indian cobra (Naja naja) kills several thousand people annually, mostly because it enters houses to catch rats. The king cobra (Ophiophagus hannah) is the world's largest venomous snake, often more than 12 ft (3.5 m) long. Some African cobras can spit their venom more than 6 ft (1.8 m). Cobras are favourites of snake charmers, who, by their movements rather than their music, tease the deaf snakes into assuming the upreared defense posture.