As people have said above it is dangerous. Especially drinking a lot at once. Your system cannot adjust or eliminate fast enough and it can lead to flooded tissues and electrolyte imbalance, possibly death.
If when you urinate your pee is clear like water, you are plenty hydrated, no need to keep loading up on water.
The amount of liquid (water is deceptive because some people think water is different than a coke or apple juice, but pretty much liquid is liquid) you should consume varies depending on your weight, muscle vs fat percentages, whether you are sweating off water, how active you are, etc.
The old 8 glasses a day is assuming the person is eating properly we get hydrated from the foods we eat also, and an average man, which is actually lower in weight than the average now, and it is 8 ounce glasses, and most people have no clue what an 8 ounce glass is, because most glasses are much larger now. Look at your grandmas glasses compared to yours. And, that was a standard for not being out in the heat all day or exercising.