Author's note: The idea of Tom as a voluntary Controller came into my head fairly recently. Of course, there have been fics about Tom later joining the Peace Movement, being freed, and even never becoming a Controller, but leading the Animorphs instead. As someone who writes-or at least begins writing-a lot of "Yeerks as the good guys" fan fiction, the idea of Tom being infested from the beginning with a decent Yeerk seemed too interesting to pass up on writing.

I readily admit that it's been years since I've read most of the books in the Animorphs series, but from what I remember, Tom-or rather, his Yeerk- didn't start pushing Jake to join The Sharing until the beginning of the series. That makes sense, because if he had been bugging Jake for months beforehand, Jake probably would have joined, gotten infested, and the Animorphs series would exist with him only as a minor character. So, in an event to make the events of this story as close to the original series as possible, I am infesting Tom two weeks before Elfangor came to Earth.

I also don't plan on rewriting the entire series from this AU perspective. For one thing, it would require getting my hands on, and rereading all of the books, something I neither have the time nor the motivation for. That being said, if my motivation to write this thing lasts longer than it did for some of my other pieces, I will jump ahead to key parts in the series. I already have more than a vague idea for the ending. So, with that, I hope you enjoy what follows!

The Switch

As soon as I entered the room holding the meeting for the Full Members, I realized I had made a mistake.

Well, that was putting it mildly. An epic fail, really.

At first, I didn't see or hear anything out of place. For the first 2.5 seconds. Then, I spotted what I assumed was someone wearing a Halloween costume and everyone listening to him intently. But what really threw me was that the creature was speaking into everyone's head (mine included) and not using words.

I kind of freaked out then, and there was no recovering from that.

Looking back, had I played it off as some kind of pre-Halloween AKA pre-April fool's joke, I might have gotten away. Would have thought that in addition to being a cool community organization that had fun activities and prided itself on helping the needy, they also had a sense of humor. It may have incited them to ask me to become a full member earlier. I definitely wouldn't have wanted to quit, then.

Of course, the end result would have been the same, although maybe a few weeks later. I still would have become a Controller...just could have enjoyed my pre-Yeerk days a little longer.

Maybe it worked out for the best this way. I might not have become a voluntary Controller if they had waited.

I initially joined to get close to Allison, a really cute girl who I just started to get to know that year. Starting high school meant the combination of several middle schools throughout our district, and while the number of students in each class didn't change-all of our parents had voted to keep the average size to twenty-five students or less-the number of students in our grade exploded. People like Allison, who I'd never seen before, were now my classmates. Not only was she cute, she was popular, and smart. In a bunch of advanced classes, if what I'd heard was true.

I wasn't exactly the Mr. Popularity or Mr. Ivy League In Training of my grade, but I was talented at basketball, which got me some points with my classmates (and the girls), and my grades were decent enough. When I heard that she had joined this community group called The Sharing, I decided to check it out. Maybe we could get to know each other better.

Allison seemed to know that I was interested, because we'd hang out together at some of the events, and she always said hi at the meetings. And while we hadn't exactly gone out on any dates, once we'd held hands during a barbeque at the beach. She'd asked me about becoming a full member, then, and I asked her how it was different than what I was now.

Her answer hadn't seemed all that suspicious, but I probably wasn't encouraging enough in my response. I wouldn't say that things cooled down after that, but I noticed her going to those full member only meetings more than usual. I got it into my head that there was a guy she liked in those meetings, and I wanted to tell her that I really liked her, and if that meant becoming a full member of this club, I was up for that.

I didn't see her again for a couple of weeks, and when I did, she hurried into the full members meeting before I could say hi and tell her everything. It dawned on me that she was probably already seeing someone else.

I only hesitated for a minute before heading in. That's when I saw who I thought was the guy in the Halloween costume, and shortly after that was when I began freaking out.

Because thoughtspeech, as I later learned, isn't something that you can fake. Maybe I still could have pulled off an escape, had I been quicker to think of a joke or even just pretended not to hear it. Or even acted like I was already a full member and this sort of thing was totally normal for me.

The reaction was immediate, and the next thing I knew, I was being dragged through a door-not the one I came in-and down a flight of stairs. I didn't remember what I was saying, but I remembered being more in the state of disbelief (because of the thought speech) than in a state of panic. Not that I was okay with being dragged somewhere against my will, but I was more confused than flat out terrified.

The fear kicked in when I heard the screams, and panic kicked in when I got a glimpse of people-and other creatures covered with blades-in cages. There were a couple of lines to what looked like a giant pool, and both lines had people and the bladed creatures. Other bladed creatures were directing the front of the lines, and in the second line, some people looked calm, while others were being held still by more bladed creatures.

I must have asked something like, "What in the hell is going on?" because I distinctly remember one of the humans in the second line tell me, "You're in hell."

The four or so people who had been dragging me this far-and banging me up a little along the way, judging by a very sore cheek and some blood dripping from my nose-said something about how I had to go immediately. One of the bladed creatures who hadn't been burdened with incapacitating another human grabbed an arm and another one quickly followed. The other humans let go, but they didn't leave.

They nearly dislocated my shoulders pulling me to the ground, which was probably my fault because I was still trying to fight them off. Adrenaline high, probably. One of them grabbed my head and forced it in the water.

No, not my entire head. I could still breathe. It was just my right side. My head, up to my ear, was submerged, but the rest of me was still above the pool.

All I wanted was air, and I was only dimly aware of a sharp pain in my ear that quickly faded. Then, the feeling of something crawling inside, and if my hands hadn't been in the grasp of the bladed monsters, I would have temporarily overlooked the lack of air to try to pry the thing out.

Maybe it was silly, but somehow, that gave me a sense of relief. Whatever the aliens were planning on doing to me, death from suffocation wasn't part of the plan.

Yet.

Maybe it was silly, but I stopped thrashing then. What was the point? Two bladed aliens were holding me down, and even if it had just been one, I doubt that I could have fought them off, adrenaline high or not. Everything that had happened in the last couple of minutes had been due to my rushing into things. Maybe, I should just take a minute to figure out what to do next. After all, I was pretty uncomfortable, dangling over a pool of murky water, but I didn't feel any immediate pain, so probably, my life wasn't in immediate danger. Sure, I had no clue what was going on, but...

Suddenly, I felt something soft push up against my ear. Instinctively, I tried to move, but the aliens tightened their grasp on my head. I heard words that didn't sound like English-well, of course, aliens probably didn't know any Earth languages-and then, a sharp pain in my ear. Before I could shout, it was gone, replaced by this feeling of something pushing itself inside my ear. Some kind of injection, maybe? The alien equivalent of anesthesia before an operation?

Except, I could feel the movement inside my ear continue. No more pain, so it probably had been a numbing agent, but that wasn't exactly reassuring. Were they going to do some kind of brain surgery on me? Kill me outright? Was the numbing part of some kind of euthanasia, the kind that some states gave prisoners before a lethal injection? I'd never given it much thought before, the painkiller before the execution. If that was what was happening to me, was I supposed to feel glad that my alien killers were humane enough not to want me to suffer as they performed a brain procedure that would lead to my death?

As these morbid thoughts crossed through my mind, I became aware of the numbness spreading from my ear throughout the rest of my body. Without much logic. Like, first my right arm seemed to go numb. Then, my left eye. Then, my tongue. Eventually, I became aware of the fact that I couldn't even do as much as blink.

Except...suddenly, my body was behaving normally. My mouth spoke, saying it had control. Suddenly, "I" was getting up, being assisted by the bladed aliens.

Control? I had control? No, control was definitely something I didn't have.

(Calm down,) a voice told me. (It's all right.)

Great. Not only was my body going on like I wasn't even there, I was hearing voices.

Not just voices, either. Emotions, belonging to the voice. A mix of confusion, uncertainty, and even fear. Well, closer to apprehension than fear.

The fear was all mine.

There were good ones, too. Excitement, awe. Mostly as it used my body to move around, my eyes to take note of my surroundings. Despite the hellish place the aliens had taken me, this voice found pleasure in being able to look around and, almost more importantly, see everything. Not that the voice told me these things in words, but the emotions themselves gave it away.

(You're not hearing voices. At least, not in the sense of going crazy, as you would say,) the voice replied, sensing my bewilderment. (I'll explain it all in a few minutes, but for now, know that you have nothing to fear.)

Was I dead? Was this voice some kind of an angel or something?

(No...Tom,) the voice replied, pausing before saying my name. (You are certainly not dead. Just, try to relax. It will all make sense soon.)

Had I been in control of my body, I might have become sick. I was still vaguely aware of the dizziness caused from my head being forced under water, not to mention the matching pain on both hands. Plus the bloody nose and banged up cheek. Yeah, it had really been a great day.

My body moved past the rest of the people and back into the room. It slowed before standing before the Halloween costume guy.

"Visser Three," my voice acknowledged.

(Glad to see that problem was taken care of,) came the thoughts of the creature. (You are?)

I was 99.9% sure it was no longer a human wearing a costume, but my mind couldn't think of anything except "creature" to describe him. Well, maybe "monster".

"Terlin six-five-seven of the Hett Simplatt pool," my voice replied.

My vice principal, Chapman, who I had seen at numerous Sharing activities, spoke up. "Is there any resistance from your host...Tom?"

"He's confused," Terlin replied. "I will explain everything to him shortly."

Chapman nodded, and the monster spoke again. (If that is all, you are dismissed, Terlin.)

Terlin nodded, said something about a candle, and then left the room.

(Kandrona, not candle,) he told me. (It's a replica our sun.)

One question down, a million to go.

(You can just think your thoughts at me,) Terlin told me, and his tone changed from teacher to something more gentle. Or maybe it was just wishful thinking on my part. (This was not how I hoped things would go.)

(That makes two of us. When are you going to explain things? Like, why can't I speak, or move?) I asked him. Was it a him?

(We don't have genders the way you humans do, but for the sake of simplification, yes. I am a "he",) he replied, moving my body in what I assumed was the direction of my bike. Then again, I had been wrong about a lot today, so it wouldn't surprise me to be wrong about that, too. (You can't move because when I entered your mind, I took control of the nerve centers of your mind, so they react to my commands instead of yours. As long as I have control of them, you will be unable to do anything on your own. Your thoughts, however, will still be yours to control.) Terlin kept the pace of my bicycle steady as he "spoke", while my horror grew as this new reality sun in. (As you guessed, we are not from your planet. The bladed creatures you saw are Hork-Bajir. The Visser's host body was an Andalite, and it is probably the only one of those you are likely to see. Both of them, along with the humans who escorted you to the giant pool and nearly killed you, are controlled by my species. We are called Yeerks.)

Then, to my surprise, he sent me an image of what looked like a slug. (We are several inches long, and unable to see at all or hear much in our natural state. Our sense of touch, however, is excellent, and as you can tell, we are very intelligent. Unlike your Earth slugs.)

He waited for me to react, and while my first reaction was disgust at the idea of a slug inside of my head-or wherever he was currently residing while controlling my body-my more immediate concern was just how sanitary it was for an alien to be living inside of me. If I wasn't going to, at the very least, break out in hives, and at worst, die from exposure in an hour or so.

(No, no, Tom, you don't have anything to worry about on that end.) Terlin's voice became reassuring, and I could have sworn I could hear a stifled laugh. (We are parasites, yes, but our presence in the mind of our host-which is where I am living-does not affect the host's body adversely at all.)

(So, I'm not going to die from some weird strain of an alien bacterial infection?) I asked.

(That's correct.)

That was a small relief, I supposed. Although, given that my body had been taken away from me for an indefinite amount of time by an alien, I wasn't so sure if dying from its/his presence would have been so bad.

(You were afraid that the bladed aliens were going to kill you by removing parts of your brain, and now you would prefer to die from an infection over living with me?) Terlin sighed. (Well, I can't say I am surprised. Few take well to infestation, at first.)

(Infestation? That's what's going on now?)

(That's what happened when I entered your mind and took control,) Terlin corrected.

(And took over my life,) I added, sourly.

(Well, if that's what you're concerned about...)

Slowly, I could feel myself regain control. I was glad that it had been gradual, because otherwise, I could have fallen off my still moving bike. Not for the first time, I couldn't wait until I turned 16 and would get my dad's old car. No more getting around on this thing that I'd gotten when I turned thirteen.

My mind must have registered my shock, because Terlin addressed my unasked question.

(It's not necessary for me to be in control of your body the entire time. Only when I am around my fellow Yeerks. But,) he added, (it IS necessary for you to cooperate with me, which means not screaming about aliens to your fellow humans.)

(I didn't!) I protested, hands clenched on the handles of my bike, afraid that the Yeerk was going to take control again. He didn't.

(No, Tom, but you were thinking of it,) he chided.

Had I been? Maybe deep in my head, but not consciously. Not at that moment.

(All of your thoughts are visible to me, Tom,) he explained. (Not just the ones you address at me. Likewise, I can access all of your memories.)

I scowled. (That's got to be an invasion of privacy.)

(I agree,) Terlin replied. (But it's nothing that I can control.)

That was a little better, but it still hardly felt fair.

(It's not. If it helps, I won't use it against you.) At my confusion-what else was new?-Terlin explained, (There are Yeerks who replay their hosts' memories, both bad and good ones, as a means of discipline. Both as punishment for acting out, as they see it, but also as a way of subjugating their host. Those Yeerks are generally the ones in positions of power, which I am not.)

A thought occurred to me. (Is Visser Three one of those Yeerks in charge?)

(He's the leader of all of the Yeerks on this planet. Not the highest of all Yeerks...that's the emperor. But the visser's rank is closer to his than most of us can ever hope to be. Should we aspire to power.)

I got the sense that Terlin didn't particularly want that power.

(You're not incorrect,) he told me. (I serve the empire, which is the form of government the Yeerks have adopted for as long as we can remember. But I am not particularly ambitious, as long as I have a decent host body. Preferably one who is voluntary.) After a pause, he added, (Someone who doesn't object to my being there.)

While I would hardly have considered myself voluntary, I had to admit that I objected to Terlin's presence a lot less now that I was back in charge of my body. I could only hope that it would last. Obviously, I didn't know much about Yeerks at this point, aside from their desire to take over humans, but Terlin didn't seem too bad.

(And...that's me?) I confirmed. (Your host body?) I didn't say anything about not being voluntary. If he could read my thoughts as well as he claimed, and I had no doubt that he wasn't lying about that fact, well, Terlin already knew that part.

(Host, for short. Yes.)

(Why do you need them?) It didn't seem like an outrageous question. Sure, without a host, they were stuck in a pool, but at least they didn't have to take people, or other aliens, over. Wouldn't have to deal with their questions or their protests at their minds being invaded, their bodies no longer theirs.

(It's true that we do not need host bodies in order to live. As long as we were in a liquid substance, receiving nourishment in the form of the Kandrona every three days, we could exist that way. As it is, we have to return to this pool every three days to absorb the rays and the nutrients for a few hours, or else we will die. The humans and Hork-Bajir you saw at the pool…)

Here, he paused as I took a minute to digest everything. (The bladed creatures.)

(Exactly.) He paused again. (Do you want me to continue?)

Oddly enough, Terlin sounded tentative. Enough so that, even if I hadn't been in control and strongly objected to his presence, I probably would have agreed, if only to have more information to figure out everything I needed to know. In order to understand what was going on.

(We can exist without host bodies, under these conditions,) Terlin explained. (But in our natural state, we cannot see, have extremely limited mobility, and are nearly deaf compared to the hearing of most hosts. The only sense that gets duller when we infest a body is touch, and that pales in comparison to being able to see and hear. And not just that. Can you imagine being able to move, truly move, or lift objects, after living your life as one of your helpless slugs?)

I could understand it. Sort of. At least, it made sense to me, why Terlin and other Yeerks were willing to take over the minds of other beings in order to have a better quality of life.

But the screams from the people and the Hork-Bajir at the pool made me realize that the Yeerks' happiness came at a cost. How many humans and Hork-Bajir were basically slaves inside their heads, only able to get their bodies back for an hour or so every three days, just so that their Yeerk could experience a better life?

On the other hand...Terlin was in my head now, and he could see and hear with me in control as easily as if he was in charge of my body. While I wasn't exactly sure if I wanted him there long term, I couldn't say that I wanted to scream just because he was there.

Okay, the fact that he could read my thoughts and see all of my memories was creepy, but he'd promised that he wouldn't use that to hurt me. True, I couldn't know what he would do in a few days or a few months, especially if I ticked him off for some reason, but wasn't a promise not to use that as a way to hurt me better than nothing?

It was a lot to think about. I felt Terlin tugging at my mind. Not grabbing control, exactly, just calling something to my attention.

We had arrived at my home. I made to get off my bike, but suddenly, I couldn't move.

(Hey!)

(Sorry!) he said, and withdrew control. (It's a habit.)

I took a deep breath and parked my bike outside of the garage. (Can I go inside?)

He sent me a mental nod. (You can't say anything to your parents, or your brother.)

(Well, for one thing, they'd never believe me. They'd have me committed. But I figure you'd take control so quickly that I wouldn't be able to.)

The last part came out a little harsher than I intended, and Terlin flinched mentally. At his silence, I opened the door and called out-as per usual-that I was home.

Not hearing any response, I headed in the direction of my bedroom. It would be a couple of hours before dinner, and maybe I could rest a little before then. It being a Friday, I didn't have any homework that needed to be done immediately. I caught a glimpse of myself in the bathroom mirror on my way to my room, and froze.

Ugh.

(We should probably get you cleaned up,) Terlin told me, not unkindly. (The Hork-Bajir and other humans certainly weren't gentle when they took you to the Yeerk pool.)

(No kidding.) I studied myself in the mirror. Scratches all over my hands and arms from the Hork-Bajir blades. What looked like would become a left black eye. Bruised nose, but upon further inspection, it definitely wasn't broken. (Am I going to need a tetanus shot from the Hork-Bajir cuts?) I asked Terlin.

(Doubtful. As long as you use enough soap and water, and perhaps some of that human alcohol. The rubbing kind, not the drinking kind,) he confirmed.

He let me get cleaned up on my own, and afterwards, I headed into my room. Still at least another hour and a half before dinner, and mentally and physically, I was exhausted. I climbed on top of the bed without bothering to remove the covers. Shut my eyes, and waited for sleep to take over.

(Tom?) came Terlin's voice.

(Yeah?)

(Look, I know it's a lot to take in. It always is. But me being here...it doesn't have to be a bad thing. There are many humans who want us there. They've formed a type of symbiotic relationship with their assigned Yeerk. Even some Hork-Bajir.)

(Do they really have a choice, though?) I asked. (I mean, suppose they tell their Yeerk, look it's been great, but I don't really want to be a part of an alien invasion anymore. Go find another human, or better yet, just live in the pool. I just want my body back, permanently. I'm guessing their Yeerk would laugh in their face. Or, in their head.)

Terlin sighed. (It's not exactly something we asked for, either. At least your slugs aren't sentient beings aware of all they're missing out on.)

(Yeah, evolution kind of bit you in the butt there,) I agreed. Then, (Do Yeerks have butts?)

Terlin took a moment to consider this. (I don't believe so.)

He was quiet for a little, as though thinking of something to say. Lucky him. He could keep his thoughts to himself.

(Sleep well, Tom,) he told me, finally.

As exhaustion finally won out, my last thoughts before losing consciousness were that I didn't dislike Terlin. I could see that he was trying to be a good guy, at least for a Yeerk. And except for infesting me against my will-and given what had happened earlier, if it hadn't been him, it would have been another Yeerk, and possibly a cruel one at that-he hadn't really done anything so far to make me dislike him. I was even starting to get used to his voice in my head. Which was pretty bizarre, considering that he'd only been there for a couple of hours. I didn't know if I wanted to take the leap and consider myself a voluntary Controller, but did I really want to spend my only time without him locked in a cage, listening to the screams and cries of other involuntary hosts?

A/N: If you've read this far, please take a minute to write a review!