She would bury it in her yard, in the light of a full moon, trying to hide her tragic mistake. Her friends would ask her about it. "Where's that new kitty, Fluttershy?"
At first it was easy to make excuses. "He's sleeping today," or "He doesn't like going out." Eventually she told everypony that the kitten was adopted.
But the guilt wears on her. She can't get that dying scream out of her mind. It haunts her. Why didn't she check under the wheels before she pulled the cart forward? She can never take that back.
Everything reminds her of that moment. She was trying public singing