She had learned two of the Unforgivables, practicing on magically enlarged spiders like the ones Professor Moody had used in fourth year. The only Dark spell she had never been able to cast successfully was the Cruciatus Curse. Her repeated failure had sent her into tears at the thought of disappointing Lucius, until he had explained that he had never expected her to succeed, that it was not in her nature to truly wish suffering upon another and that if this ever were to change, she wouldn't be the witch he knew and desired.