At one point in Shin Godzilla, Toho’s 29th entry in this ancient series, a character calls Godzilla a “perfect organism.” This might sound familiar to anyone who’s watched Ridley Scott’s Alien (1979): it’s how the devious android Ash describes the xenomorph. Godzilla movies don’t typically reach outside the big guy’s cultural bubble, the occasional crossover with King Kong notwithstanding. They exist within a cloistered half-century of constant reinvention; there are whole eras of Godzilla named for whoever was emperor of Japan at that time, all refracting and, frankly, diluting the original premise into a repeatable formula that yielded enjoyable-but-inessential riffs on everything…