Link accidentally whines at a critical moment, causing Midna to picture herself as a wolf, and making it so.

The ritual began quietly, as Midna began pouring her magical reserves into the circle, into the spell. She kept picturing Link as he should be, as a person, as a Hylian. They’d spent so much time together on their adventure, picturing him that way didn’t take much effort. For so long they had been travel companions, partners, best friends. The time without him had been...more difficult than she had expected. The magical energy was beginning to reach a point where it was spilling out into the air, raising the temperature of the room little by little as a byproduct. Wolves, she soon found out, didn’t react well to sudden heat like that, as Link let out a whine than momentarily disrupted her thoughts.

For reasons she was never able to place, Midna’s mind immediately wondered how odd it must be, to be thrust into a different form like that. Sure, she’d been cursed into an imp, but at least that had been humanoid! Poor Link, stuck as a beast, as a wolf. What would Midna be like as a wolf? What sort of existence was that? It was just then, too late to stop it, that she realized that the spell had reached its peak, but instead of picturing Link in her mind, returned to his natural form, she was visualizing herself as a wolf instead. With only that framework to draw on, the spell reached out and seized her body, and Midna’s eyes widened in terror. The change was quick, as it had always been for Link: the crunch of shifting bones, the ruffle of fur growing all over the body, and the distinct sound of a humanoid scream turning into a canine howl.

Link looked at his friend in astonishment, utterly confused. Before his very eyes, Midna had transformed from the Twili woman he knew into a black-furred wolf with orange eyes, a female wolf with a lithe frame and the scent of a bitch. Part of him was terrified at what had happened to his friend, but another, more bestial aspect of his nature wanted to get to know this wolf better. Throwing those thoughts aside, Link whined, communicating to her his sadness over this mistake. How were they going to turn back?

Surprisingly, that more complex message must have come across somehow to Midna, who looked him in the eyes with a fierce expression on her muzzle. She made a growling sound, one that Link could understand as well as human speech. “This is bad, but it could be worse. We could try using the ritual again, but it’ll be even harder to keep up my concentration like this. It’s possible for me to try using my raw magical abilities to sort this out, but that result could be very unpredictable. Then again, the magical enchantment on myself could run out, and we could try waiting for it to possibly end. What do you think, Hero?” None of the options were exactly appealing, but Link made up his mind on their course of action.