The X-Men's Most Powerful Hero Turned Herself Into A Dinosaur
Rachel Summers is famous for being one of the X-Men's most famous fighters - and that was before she turned herself into a dinosaur!
Believe it or not, the X-Men's Rachel Summers once transformed herself... into a literal dinosaur. Although the X-Men comics are supposed to be about themes like tolerance and equality, the franchise seems to love time travel more than any other superhero franchise. Rachel Summers - or Rachel Grey, as she calls herself now - is one of the crazier examples.
Rachel originates from the alternate future timeline seen in "Days of Future Past," where mutants and humans were locked in an apocalyptic war. She was the daughter of Cyclops and Phoenix in this timeline, before she was eventually blasted back to the present day, where she understandably struggled to figure out how she fit into everybody's lives. Rachel is one of the most powerful X-Men, generally treated as an Omega Level mutant, although current X-Men 'Omega' rules appear to have retconned that.
Legendary X-Men writer Chris Claremont returned to the franchise in the early 2000s, and he wasted no time bringing Rachel back to the team. In one arc, "World's End," he had the X-Men confront a race of dinosaur-people called the Hauk'ka. This ancient civilization had evolved millions of years ago, and a last colony of Hauk'ka survived the extinction of the dinosaurs by taking refuge in the Savage Land. They even featured mutants of their own - including a telepath who took control of Rachel Summers, psychically persuading her she was actually a Hauk'ka who infiltrated the X-Men. With Rachel's help, the Hauk'ka were able to beat the X-Men - and then they were shocked to realize just how potent this psychic gambit had been.
The Hauk'ka hadn't reckoned on the sheer scale of Rachel's telekinetic power. Rachel's subconscious mind began using telekinesis to rewrite her biology on a genetic level, gradually transforming herself into one of the Hauk'ka. The X-Men were staggered at Rachel's apparent betrayal, but quickly realized she was under the influence of an outside force, especially when they saw her biology beginning to change. Fortunately, in the end Rachel's mind was put right, and her subconscious began restoring her to normal. Thankfully, this was done before Rachel fed - the Hauk'ka are carnivorous.
Chris Claremont has always liked toying with themes of self-identity, and as a result there are striking parallels between "World's End" and the more famous "Dark Phoenix Saga." The difference, of course, is that in Jean Grey's case the psychic Mastermind was unlocking the dark side of Phoenix's nature, whereas the Hauk'ka were creating a whole new persona. What's more, the "Dark Phoenix Saga" is frankly a whole lot less crazy in the larger X-Men lore, given it didn't involve Jean morphing into a dinosaur.