'The Mare In The Moon' wasn't the only legend that Twilight read that fateful day. And just like the aforementioned legend this one was also true. it just happened earlier than the other, and Twilight is 'dead' center of the legend.
A human of low character dies and gets sucked into Equestria as a copy of Twilight. The new mare then proceeds to cause chaos for the ponies, but she tries to help... and, more importantly, make some money
When Twilight Sparkle's Ascension has an unanticipated side effect, the newest princess and her friends must help a second Twilight adjust to her new world...though the mind inside her has a secret that would surprise her new friends.
After his sudden death on his way to school due to an idiot driver, Ken Williams wakes up to find himself as a strange quadruped with wings and a horn.
When a man finds trees tall as his waist and an ancient castle with furniture much too small for him; he comes across the inhabitants of the new world. The thing is, he can hold one of them in the palm of his hand.