Apologies in advance for being blunt, but, uh...
This kit is quite broken.
So, I'll start with the elephant in the room. His ultimate. While it's difficult to say, since the duration isn't noted, but this appears to be probably the strongest ability in the game. At worst, it's a ridiculously powerful cc/displacement spell; a suped up charm/fear (compare/contrast the power of Sylvanas's Mind Control from HotS). In its most powerful use case, you steal their carry, murder a support and then watch as their own team murders the marksman by having them body block all the skill shots. Even if it ONLY allowed you to control their movement, it'd likely be a very powerful spell. That you also get what is more or less a guaranteed Mordekaiser ghost is absurd.
The next issue is his W. I'm not particularly kind to damage reflect abilities in general, and this one irritates me in just how disparate the potential effects are. Veigar's already been brought up, but most burst mages won't appreciate such an effect. On the other hand, having this popped by a single Rumble Q tick seems like a massive feel bad for Scryr.
His Q is an odd duck. It's potentially a powerful pushing tool depending on the numbers, but also denies your ADC gold, which seems like an unfortunate design choice.
His E is... An ability. It's not a bad idea, per say, but it's very bland, and doesn't seem to have any synergy with his kit.
His passive is just... There. It feels tacked on. It's low impact and only even affects two of his abilities (and only one of them in a meaningful way). I'm pretty sure there'd be nearly no difference if this was just added to his Q.
While I can appreciate the attempt to be thematic, Scryr breaks a number of design rules in what feels like more or less unsalvagable ways. Beyond that, while his abilities share a theme, they don't actually feel like a coherent kit. He has a push enabler, a harass ability, a personal defense tool and the most powerful teamfighting spell in the game. If you consider what such a champion would do if dropped into the game, even with potentially undertuned numbers, I doubt anyone would be pleased with the result.
EDIT: Okay, having gotten some distance, I'm now less salty, so I think I have some constructive criticism rather than just complaining.
I think you may have tunneled too hard on the literal effects you want to see: a champion that messes with the enemy's head. I feel that, with a little work, you can find something that creates the impression of the champion you want without having to out and out use the exact mechanical effect you expect. League is often a game of abstraction, where unusual effects are boiled down to what is achievable and balancable. Rather than just saying 'you control the enemy', perhaps consider an effect that simulates such an effect. Doing so would also help engage Scryr with the fantasy of his character; despite appearing to be a tricky, deceptive champion, he feels like he relies too much on brute force cc right now.
Alternatively, perhaps you might consider gating his current effects behind other mechanics? Part of what hurts his flow as a champion is that there's a distinct lack of a unifying play style. Tying his abilities to a mechanic would likely allow you a lot more room to craft a proper mentalist, while also giving him more depth to his kit.
or 
or even 
as a good examples of what having one strong move can do for the rest of your kit... with the move up, they are hard to beat. without their ults... they are next to useless.
ults you, or 
ults you, or 
ults you.... etc..etc...etc... your measly little ability will completely destroy anyone on the map. Seems balanced?