If you drink copious amounts of alcohol in one sitting, you can get alcohol poisoning. The alcohol concentration in blood and in the brain becomes so high that you can lose consciousness or slip into a coma.
Ultimately, the central nervous system can become slowed down to such a degree that it paralyzes the respiratory system. This can be fatal. In adults, alcohol poisoning can already occur at four per mille, in younger and inexperienced drinkers this is much lower.