The Gone was a term referring to the point of no return for a person who had caught the Flare and had turned into a Crank. Usually, it was used as part of the term "Past the Gone."
When a Crank is past the Gone, he or she would be incurably insane, unable to control their thoughts and turning to instinct-driven animal-like behavior and cannibalism. They had lost all of their human personality. These cranks were the most dangerous type of crank and were rare, but not uncommon. They were first seen in the Scorch during The Scorch Trials.