Snakes Conquer Earth is another setting I've been thinking about a lot; at first the snakes were very aloof and distant and hard to understand, but one of the things about alien encounter stories is that a lot of writers/thinkers agree that they'd still propelled by self-interest, which will likely result in our destruction. But if they're propelled by self-interest, they might actually be more like us than we presume . . . Also, although the Snakes are agender, they still have a method of DNA exchange that relies on personal contact--concerning which, they're not allowed to mingle with high-ranking officials. Given that snakes are quite literally attracted to superior rank, this can cause a lot of tension (even if it results in a tight-knit affection-based hierarchical system) . . .