I don't own them. It's all JK Rowling's. I'm just borrowing them for the moment.
It was a cloudless night, and the full moon rose brightly overhead. Severus was in the Forbidden Forest, gathering materials for some complicated potions he planned to brew. This was a task he enjoyed, as it allowed him to forget about the stress and strain dealing with the Dark Lord and Dumbledore.
He came to a clearing and shaded his eyes as he noticed a dazzling white unicorn standing placidly near a tree. Much to his surprise, a very thin, dishevelled Hermione Granger was sitting under another tree. He blinked several times, not believing what he was seeing, as he thought Miss Granger was on the run with Potter and Weasley. He quickly cast Disillusionment and Silencing charms over himself and hid behind a tree.
The unicorn slowly approached Miss Granger. Her eyes widened as she regarded the majestic creature before her with its golden hooves and magnificent horn. From his vantage point, Severus watched as the wondrous creature carefully shifted its head close to the girl. It nuzzled its nose against her head, and as her eyes closed she appeared to lean into its touch. She opened her eyes and hesitantly raised her hand toward the unicorn's nose. It sniffed her and nuzzled its nose against her hand.
She stood up and regarded the unicorn with a look of awe. She hesitantly raised her hand toward its neck and stroked it, gingerly at first, increasing the pressure and the length of the strokes as the magnificent creature indicated its pleasure by exposing more of its neck to her. "Thank you," she murmured to the unicorn. "Thank you for the reminder that there is still beauty in the world." She gave the unicorn a brief embrace, and then she backed away from it slowly. It bowed its head toward her and started walking away from the clearing, disappearing behind a tree.
Severus was moved by what he saw and noticed that Miss Granger seemed rejuvenated after her encounter with the unicorn. She had a smile on her face as she turned and Disapparated back to wherever she came from. Severus sighed as he replayed in his mind the scene that unfolded before him. He removed the Disillusionment and Silencing charms and then moved on to continue his foraging in the forest.
A/N: Prompt issued by ladyinthecloak: Snape watched as the wondrous creature carefully shifted its head close to the girl. Thanks go to silverdoe for answering my question about petting horses.