Starlight looked at the spell, prodding it with her magic, trying not to think about the destruction it was raining down onto the city below them. The added tension would do her no good, and save her no time. She was, besides, already nervous enough at having to interact with the thing in front of her.
If she'd had to describe it succinctly, she would have simply said it felt wrong. On some primal, instinctual level, it felt like it went against what magic was supposed to be. It wasn't something she logically deduced, though she could have probably done so if she'd had the time, it was a feeling. It was something that latched onto her basic, natural understanding of magic as a unicorn, and sent chills down her spine. Whether it was the spell itself, its nature and purpose, or the process used to achieve it, something about it was unnatural in the worst way. Something about it shouldn't have been done the way it had been.
Starlight tried to focus and deal with the spell analytically, but still she couldn't deny the effects its nature had on her. Saying it made her uncomfortable would have been an understatement. Ripping cutie marks away from ponies against their will had felt more natural than trying to interact with that spell. It was like operating on a festering wound on the structure of magic itself.
Her magic prodded a little deeper. Slowly, methodically. If she went about it as mechanically as she could, she almost managed to take her mind off the sheer unease that having to be aware of the spell to that degree brought along. She felt around its edges again. She'd found the point where it connected to its power source, and potentially received other kinds of directions from too, but not a way in yet. She couldn't just force herself inside there, the thread connecting the spell to its source would most likely collapse and then reform. She had to get in through the spell, the regular way.
That meant going deeper into it. Magic flowed through her horn a little more intensely, as she tried to get a better feel for the inner workings of the magical manifestation in front of her. It was, again, an unpleasant experience, but at the very least the basic structure and design of the spell seemed to be relatively comparable to the kind she was familiar with and easy to understand for her. She probed deeper still. It was much like feeling around inside a hole in the ground with a stick, or like trying to pick a lock, only everything was a lot more wiggly and vibrating and abstract. Sometimes she visualised it as tentacles sliding around inside a maze, before the amount of dimensions involved made her mental image fold in on itself.
But in the indescribable shape of the magical construct she was exploring with her own powers, she seemed to find something. Something like a connection, a gateway leading out of the main structure in front of her. She latched onto it, noted down its position, traced her magic back to find the safest path to reach it. Finally, once she had all her thoughts straightened, she pushed a little deeper into it. Then a little more still. Then, the flow of her magic reached a threshold. Swallowing, Starlight braced herself as she carefully pushed past it.