The myth and legend of vault 420 isn't really well known and I'll tell you why. Back before the bombs went off a there was a hippy town. Everyday was a festival where they listened to music, ran around naked and tripped on mushrooms, LSD and smoked really good dope. (Back then, they called weed dope)
The government shunned these hippies because they didn't follow the normal regulations and rules that everyone else followed in that era. They were basically outcasts. The government secretly decided to make a vault called 420.
When the vault was being made, they strung colorful lights, plants and water fountains making give off a pradise oasis feel to it. This was a sham, because they also set booby traps and cages full of various other creatures to be released when the vault was being used. One of these creatures was made by the government in a secret lab. This vicious animal was called the Deathclaw. It was a killing machine that was supposed to be used instead of nuclear war. Basically they wanted to release an army of Deathclaws on the enemy. The government had yet to use these creatures in combat so they decided to put some in the vault. The reason behind this, is because they didn't care about the hippies. They wanted to set an example to everyone in the future if you don't follow the rules. The government lied to the hippies and showed them the beautiful vault called 420. The hippies rejoiced in the awe of how different it was compared to all the other vaults.. to put it simply it was the ideal smoker's haven.
When the bombs went off the hippies rushed to vault and closed the massive doors. They lived in the vault for a year with no problems, smoking weed, fornication and good music. One day the inside of the vault began making mechanical noises, the walls of Vault 420 began to shift and move.
The hippies gathered in the eating area to conversate about what was happening. That's when Fred, Vault 420's DJ was grabbed from the doorway and dragged screaming into the jaws of a deathclaw. Poor Fred. The hippies stunned, watched deathclaws pour into the room and start attacking the people. Women, children and men were slaughtered. Luckily the people of Vault 420, had a massive amount of pot growing in the next room. The remaining people rushed into the growery while everyone was being massacred and began putting huge piles of weed next to the door.
Once the piles were made, the hippies threw some matches on the piles and WHOOSH they went up in flames. One of the deathclaws nearest to the pile smelled the smoke and dropped a hippie child's limb from its mouth. It's eyes began to get blurry and it felt dizzy. Soon all the deathclaws started to feel the same reaction from the smoke. In the other room the hippies were so high they were laughing uncontrollably. One hippie turned on some tunes and they all began to dance. They vibe had been set and the deathclaws imitated the hippies. Everyone was dancing. Soon the Deathclaws realized they were really misunderstood creatures. They were a product of an evil government and had been used, abused then thrown into cages. The Deathclaws apologized and shook hands with the hippies and made a pact of peace.
The peace treaty lasted for 199 years, then one day the doors creaked open. The hippies and Deathclaws were happy because it was finally safe to leave Vault 420. As everyone was leaving one of the Deathclaws realized that his mistress Deathclaw had somehow fornicated with one if the humans. A little muated half Deathclaw half human crawled out from its hiding spot in the basement. Enraged that a Deathclaw would sleep with a Human being the Deathclaw slayed the demon baby. It gave a bone chilling roar that the other Deathclaws understood. Kill the hippies.
The hippies had all pretty much left the vault as the stragglers were ripped to pieces. When the hippies heard the blood curling screaming they ran for the hills. The brutal creatures picked off the hippies who weren't able to run as fast because they were so stoned out of their minds. The closer the hippies ran for the hills, the closer the Deathclaws got. They finally reached the top of the hill and saw a small encampment of what looked like military people. They yelled to the soldiers and pointed at the massive swarm of Deathclaws pouring over the hill. The soldiers (NCR) grabbed their weapons and ran to meet the creatures. The battle didn't last long because the Deathclaws couldn't withstand the futuristic weapons. A few Deathclaws made it by crawling away from the fight. The story spread through the ranks of the remaining Deathclaws and that's why they hate humans.
Once the battle was over the NCR explained what had happened and the hippies went on their way and made a new secret hippie town were they could hide from the government. That's why it's really hard to find it. You might come across hippie town in your adventures if your lucky, you might not.
That is the story of Vault 420.. it is forever etched into the minds of humans and Deathclaws forever..