... wake in darkness.
You are disoriented, then realize the disorientation is because you are embodied. Gingerly, you feel yourself. Four limbs, a trunk, sensory apparatus concentrated at one end. Light receptors of some kind, but there's not a lot of light. Aural receptors, but either they are very dull or there is nothing really to hear. You move about a bit, trying to figure out how this kind of a body bends. Coverings of some kind encumber it, but not so much that you can't lift yourself from the soft platform your new body is stretched out on.
You try to remember how you got here. Nothing. The host mind is itself disordered, and throws up only isolated, meaningless images. It would be unfortunate if the animal you are possessing did not have a nervous system compatible with your own. But perhaps it isn't even the dominant species on this planet. Is it possible that you have taken possession of a pet of some kind?
You sway a bit, but you have sufficient control over your host's motor systems that you can move about. The floor is covered in detritus, and you feel sharp stabbing pains as you bump into or step onto things. Then you touch a wall. You run the complex appendages at the end of your limbs across it, and touch a knob. It turns, and the blockage swings away.
The next room is not quite as dark, and you are able to make out something like furniture. You regard it, and some of the noises coming from it, uncertainly. You wish you could remember how you got here. You also wish you could remember what your mission is. Infiltration and reconnaissance, obviously, but was there more?
Rumbling sounds from across the room draw your attention. There is another creature, very like the one you currently possess, near by. It seems to be in a sleep cycle. You wobble over and examine it as best you can; horrible gurgling noises emanate from an open orifice. It can't make a worse host than the one you've got, and maybe a quick change will revive you ...
You lean over it and force yourself from your current host, dribbling out and dropping into the open orifice of your new target ...
The spasms in your new body abruptly cease as you take control, and then you are conscious of your new position. Your new limbs work at least as well as those of your former host, which is now slumped on the ground. "Karl," the thought forms in your head. Good; that shows that your new host has a mind capable of merging with your own, and that it is sentient. Yes, these "humans" are the dominant species on this planet. You are now inhabiting a creature known as "Tom Ertzberger," one of several who share a domicile.
With more confidence now, you stand on your "feet" and step distractedly over your former host. Tom has his own room, but had fallen asleep, still clothed, out here. But you're not interested in sleep, and step outside of the house and into the night air. The stars—which one is your home?—shine down coldly. You sit on the hard ground and let your mind reel backward.
But there is nothing to remember, save what Tom himself has seen and heard. Karl became disorderly during the evening while watching an entertainment and wandered away for awhile; that, perhaps, was the time during which he met and was captured by you. But you have no memory of taking him. You are in a place of considerable habitation, which makes it unlikely you were wandering about in your native form. It seems probable, then, that you found Karl while inhabiting another body and seized his because you perceived a momentary advantage; it is grave stroke of ill luck that he was under the influence of mind-altering substances, and that these had an effect on you. Grimly, you set about reconstructing what you can from the images you had glimpsed in his mind.
As best you can tell, you were being held at a nearby military installation—your current host knows it only vaguely—and somehow escaped. That is where you will probably find your ship. And yet, if you had to flee that installation, it is likely because they had become aware of you, and had instruments or techniques that could detect your presence even within a host body. That would make it dangerous to attempt an infiltration—or, at least, a direct infiltration—of that installation. But that is only way that you imagine you can return to your craft and reacquaint yourself with your mission orders.
In the meantime, you could continue to inhabit this host; or you could find another. A quick perusal of Tom's mind shows that he is a marginal and unimportant figure: a youth, a student, and a slovenly one at that. He is also physically unremarkable, except for the unsightly fat that he carries about on his belly. He has no access to more important types—even his professors are completely lacking in connection and influence. There are, however, other students who might make handy conduits. A female of the species—and he knows several who are considered attractive—would probably work nicely as a host from which to ambush and seize another, better-connected host. There are also various athletic types who may be found at a gymnasium; at the very least, one of these could be a useful habitation if it became necessary to physically resist any authorities who are close on your trail.