Named after Princess Twilight, the Twilight Limit is the maximum amount of magic a unicorn can safely contain. If a unicorn passes the Twilight Limit, its hypothesized that the unicorn would have no control of the magic, which would quickly consume the unicorn, making them a pure manifestation of magic.
Applejack: "So what would happen if somepony past the Twilight Limit y'all are talking about?"
Twilight: "We don't know actually, but we theorize that they would eventually be consumed by the magic and become pure magical energy. Who knows what could happen after that."
Twilight: "We don't know actually, but we theorize that they would eventually be consumed by the magic and become pure magical energy. Who knows what could happen after that."
by MisterCooley August 11, 2014