The Ancient Destroyer Cycle is a Star Trek fanfiction series written by Rob Morris. It is a crossover between Star Trek and elements of Japanese giant monster movies, most particularly the Godzilla series. It is an alternate universe to both series.
The Three-Headed Space Dragon, King Ghidorah, rises to enormous power in a world where Godzilla was never created to oppose and contain it. From pre-history, the beast and the strange cult that worships it haunt the lineage of Captain James T. Kirk and Mister Spock. Kirk's nephew Peter is the saddest victim of this conspiracy, but may also contain the seed of hope to end the madness. Ghidorah's rampages have ended whole galaxies, and the crew of the USS Enterprise will have their work cut out for them, as the cult has seats of power on every major world - including most members of Starfleet's Admiralty.