The Ethicators

They were used to retarded life forms, but this was the worst. Yet it is a missionary's duty to bring light where there is none, for who can tell what devious forms evolution might take?
The missionaries came out of the planetary system of a star they didn't call Antares. They called it, naturally enough, The Sun—just as home was Earth, Terra, or simply The World. And naturally enough, being the ascendant animal on Earth, they called themselves human beings. They were looking for extraterrestrial souls to save.
They had no real hope of finding humans like themselves in this wonderously diversified universe. But it wasn't against all probability that, in their rumaging, there might not be a humanoid species to whom they could reach down a helping paw; some emergent cousin with at least a rudimentary symmetry from snout to tail, and hence a rudimentary soul.
The ship they chose was a compact scout, vaguely resembling the outside of an orange crate—except that they had no concept of an orange crate and, being a tesseract, it had no particular outside. It was simply an expanding cube (and as such, quite roomy) whose interior was always paralleling its exterior (or attempting to), in accordance with all the well-known, basic and irrefutable laws on the subject.
A number of its sides occupied the same place at the same time, giving a hypothetical spectator the illusion of looking down merging sets of railway tracks. This, in fact, was its precise method of locomotion. The inner cube was always having to catch up, caboose-fashion, with the outer one in time (or space, depending on one's perspective). And whenever it had done so, it would have arrived with itself—at approximately wherever in the space-time continuum it had been pointed.
When they felt the jar of the settling geodesics, the crew crowded at the forward visiplate to see where they were. It was the outskirts of a G type star system. Silently they watched the innermost planet float past, scorched and craggy, its sunward side seeming about to relapse to a molten state.