Based on the 33th chapter of Monochromatic’s The Enchanted Library :
“Sweetheart, don’t look at those,” Rarity quickly said, belatedly chastising herself for having taken off her cloak.
Twilight glanced at her, and so did her ears bend backwards and her gaze sadden. “Fluttershy told me a timberwolf left them,” she informed, returning her gaze to the scars, her magic still brushing against them. “It’s chaos magic, so I can’t fix them.”