Disclaimer: I do not own Gravity Falls or any of its characters. If I did it probably would've been angstier.

Master of the Mind

Bill Cipher was the undisputed master of the Mindscape.

He had known how to manipulate and bend the mind to his whims before most species were capable of sentient thought. He had been in hundreds of thousands of minds. He had tricked and played with the greatest of minds, and they had all knelt before him in defeat.

Stanford Filbrick Pines had been a special treat. Bill had seen him coming, known the part he could play, so he had made absolutely sure that his arrival in Gravity Falls would be inevitable. And after the scientist had begun his exploring, had actually summoned him, that was when the real fun had begun.

Stanford was one of the easiest targets he had ever manipulated. The lonely scientist's aura just screamed with his need for acceptance, for a friend. Due to the schism with his brother and his inherent need to prove himself as more than a six-fingered freak, Stanford was putty in his hands. Hell, he probably had had no need to present himself as a friend and muse and build a relationship. Bill could have shown up and just told Ford that he bet he couldn't build a portal, and he just knew that the human would have done it without further prompting.

Making Fordsey think he was a trustworthy friend and then watching everything he had slip through his fingers was just a bit of fun for Bill. A perk almost.

Though he would admit that Stanford's Mindscape was pretty interesting. It was a place of knowledge and possibilities, as endless as space.

Well, at least until Ford realized the truth. Then Bill could only cackle as the Mindscape began shifting and crumbling as Ford broke down.

Still, despite the fun he had with him, at the end of the day, Stanford Pines was just one of many minds that Bill had manipulated and ruined. Regardless of his continued significance to his plans, Stanford was just another easily-lead plaything.

Imagine Bill's surprise when he found his twin to be the opposite.

Stanley Cassandra Pines was nothing to Bill. Sure, he did have a part to play in his schemes, but then again, so did everyone else. Unlike his brother, Stanley was just a dumb joke and a waste of space, his only significance in the fact that he would re-open the portal. As he was already doing as he wanted, Bill left him alone. He really wasn't worth his time, especially since Sixer had decided to entertain him by playing a game of cat and mouse.

Bill really didn't give the younger twin a thought until that Gideon kid summoned him. It took him a moment to realize that the "Stanford Pines" the kid wanted revenge against was that loser, but then he readily took the deal. Gideon would be a useful tool later and Bill figured that if Stanley was anything like his brother, this job would be a snap.

Bill was wrong.

The moment Bill entered the Mindscape of Stanley Pines, he could tell that something was wrong. It wasn't even how the Mindscape was a monochrome, crumbling labyrinth, though he had to give the guy props for seeming so alive when he was a depressed mess inside. He might have even chuckled over how Stanley was even more of a screw-up than he appeared. No, it was wrong that he saw no signs of Stanley's inner avatar.

When Bill entered a Mindscape, the person's avatar, a vision of themselves, appeared. This let Bill talk to them one-on-one and use them a lot more easily.

Fez's avatar never appeared. Despite that, Bill could sense Stanley watching him, an oppressive glare from nowhere and everywhere.

This had never happened before.

Bill didn't like it.

Then Stanley's family showed up and Bill let them do the work after making sure they went separate ways and slipping into their ranks. That was when he noticed the second thing that was wrong.

Stanley Pines was a man of secrets. He was also a man who had undergone so much hurt and suffering that Bill was tempted to record and watch it as a movie to get some laughs from his pain later.

But you would never get any inkling of that by looking around at his memories. At least not from the ones that were actually popping up.

Most of the things appearing in Stan's mind were deceptively light-hearted. Dates, some conning schemes, making friends in prison – none of these memories showed anything more than the public persona the conman put on. The only thing that potentially hinted at anything deeper was a supposed memory of Fez declaring his intentions with the portal. Nothing new to Bill – so he had quickly shut that one.

It was after Bill opened a door labeled "Top Secret" and found a ridiculous memory that he realized it. It wasn't so much the memory that caused the realization as it was the distinct feeling that someone unseen and unheard was laughing at him.

Stanley was in control of his Mindscape. He was manipulating what they could and couldn't see. Moreover, he was mocking Bill.

That shouldn't be possible.

The Mindscape was his domain. Bill should've been able to snap his fingers and have the code in his hands within moments. Yet here he was, rooting through memories like a mere mortal.

Bill didn't know what this feeling in the pit of his stomach was, but he didn't like it.

Still, he pushed that aside as his goal came into sight.

The feeling came back though as he fought those kids. Pine Tree had figured out how to fight back, and there was no way he had figured it out by himself. Someone would have had to tell him the full extent of what could be done in the Mindscape. However, Bill knew that the brat had only been looking at memories. Unless he'd somehow interacted with a memory, which was impossible because memories were like pre-recorded sports games in that you could yell at them all you wanted but there was no way to change what happened, it meant that Stanley had managed to slip by him. Even then, it shouldn't have matter if Stanley had, because he shouldn't know what to do. The entire thing was just… unprecedented.

The final straw was when Bill decided to get serious. As he grew in his rage with the full intention of blasting the kids to kingdom come, that presence that had been hidden in the shadows since the beginning came back with a vengeance. The overwhelming anger and protectiveness that hit Bill made him pause, because it made one thing clear.

If Bill seriously hurt these kids, there would be hell to pay.

And for some reason, that sent an actual shiver up his spine.

So Bill relented. He threw off their attacks, brushed off his hat, and left. He told himself it was just because those kids would be useful in the future. He told himself that Gideon would probably make another deal with him eventually, so it didn't matter at all that this one had fallen through.

That uneasy feeling lingered though.

Stanley Pines was nothing like his older brother, but then again, the conman was nothing like any mortal Bill had ever met.

Where doors should've opened, they slammed shut. Where Bill should've easily made his way, an even more complicated labyrinth sprang up. Where Bill should've been able to talk his way out, no one had even shown up to listen to his carefully constructed lies. Where Bill should've been able to do as he pleased, he found himself being intimidated.

Because Bill could deny it all he wanted, but that was what had happened.

Though he'd never admit it, Bill was glad Fez had nothing to offer him. He had zero desire to enter his Mindscape ever again.

Because while Bill was indeed a master of the Mindscape, within his own mind, Stanley Pines was the Master.

AN: So this sprang up because what happened in Stan's mind was just so different than everything else we saw in the show regarding the Mindscape and entering people's mind. So i basically had the thought that maybe Stan could control his own mind, surpassing even Bill's skill when within his own mind.

After all, Bill had a heck of a lot more trouble than he should have finding the code in his mind. Then, Stan was able to manipulate his Mindscape in the finale in order make it almost completely blank.

Also, I'm having Bill call him Fez because we never actually heard Stan's nickname.

This is also posted on my Tumblr.