Grant Morrison is one of those writers comic book fans either love or hate. His New X-Men run led to a lot of changes for the characters and shaped their stories for years to come, but also included a lot of very weird moments. That included the reveal that Charles Xavier had a twin sister who he murdered in the womb upon sensing her evil mind, and despite being stillborn, Cassandra Nova created a new body for herself after clinging to a sewer wall as cellular matter for a number of years. This all really happened, and when she returned, Cassandra set about murdering millions of mutants and stealing her brother's body.
