Twilight was about to answer Atrocitus' question, a very curious question indeed, before the portal opened. It was almost a relief. The unicorn doubted that she'd be able to stomach what the Red Lantern intended to teach her, especially with an opening like that. Still, best not to leave him hanging. "We can talk about this after the mission." With that, she turned and walked over to Shantotto, her horn already aglow.
She still wasn't quite sure that this would work, but she gave her word and it would be a horrible thing indeed to renege on an agreement like this. Access to more foreign magic was quite the reward, no doubt about it. She hadn't had the proper time to alter the spell, but she could certainly put a few spins on it on the fly. Versatility in magic was something she prided herself on, though not overmuch. This carried its own risks, however, and she didn't want to see someone she'd only just met growing tentacles or turned inside out. The thought alone was enough to make her shiver. Putting her fears aside, she focused on the spell, on the human for. Two legs, two arms, mostly hairless. Fairly simple, really, but oh so variable. How tall could they get, and how short? Shantotto could probably pass for a small child as she was, but that was beside the point.
"You may feel a slight stinging sensation." She half-muttered as she brought her horn to touch the Tarutaru's exposed skin. It wasn't as if she hadn't done something like this before. When she was but a filly, she'd transformed her parents into common houseplants. But that had been uncontrolled, a wild burst of magic brought on by something much rarer, an event rooted in fables and folklore. Shoving these thoughts aside, she focused on the task at hand. her horn burned bright, almost blindingly so. She took a deep breath.
There was a flash of light and a puff of thick, cloying smoke that smelled of burning tin. The transformation, in sharp contrast to the long, drawn-out display of Twilight's first casting of the spell, was a quick one. Limbs extended, organs rearranged, ears rounded. In a few moments, the smoke cleared and the Black Mage was left to observe her new human shape. Twilight let out a few hacking coughs before turning her gaze to Shantotto and grinning madly. "So, what do you think?"