Fallout: Ranking Every Vault From Least To Most Horrifying
1. Vault 108 - Testing Conflicts In Leadership And Spawning Gary
Appearing in Fallout 3, Vault 108 was designed to invoke conflict amongst its residents by purposefully not filling important positions and leaving it to the Vault residents to do it themselves.
An overseer - Brody Jones - was chosen for the role but he was destined to die of cancer within three years. To make matters worse, the Vault's generators were purposefully designed to fail in 20 years (the Vault was made to open in 38 years) and the backup generator would not be sufficient to maintain the same levels of power.
There were several scientists in the Vault too, and their story is far more horrifying than its original intended purpose. They started experimenting with cloning technology, and began to create clones of a man named Gary. Each of these would be hostile towards any clones, and despite this, the scientists soldiered on and created 53 Gary clones before being overwhelmed and presumably killed by the psychotic clone army.
By the time the Lone Wanderer arrives at the Vault, it's full to the brim with the terrifying Gary clones and several Wasteland creatures.