Planet X by Michael Jan Friedman

In this crossover narrative, the X-Men are unexpectedly transported to the Star Trek universe, appearing on Starbase 88 and the Enterprise-E following a temporal anomaly. While Captain Picard and his crew work with the mutants to understand their arrival, they become entangled in a crisis on the planet Xhaldia, where young citizens are undergoing frightening genetic transformations. The crew discovers that the Draa’kon aliens orchestrated these mutations to harvest the youths as super-powered soldiers. Collaborative efforts between Starfleet and the X-Men eventually thwart the Draa’kon invasion and offer the transformed Xhaldians a chance to reverse their condition. After resolving the conflict, the X-Men use a timehook device to return to their own reality, unaware that their journey was a calculated game played by the omnipotent Q and the Watcher.