Animal Instincts

With her student slowly becoming a changeling, Celestia must convince Twilight to give into her desires before she is lost forever.

After a diplomatic mission goes awry, Twilight is struck with a venom that has her slowly becoming a changeling. While her student fights to retain her sense of goodness, Celestia must convince her to embrace her new powers and take the love that will save her from becoming a drone... through any means possible.