Why does Harry use Felix Felicis in "Harry Potter and the Half-Blood Prince"?
To extract information from Professor Slughorn.
<s>[INST] <<SYS>> Answer as briefly as you can to the following question. You are required to give a one-shot answer: <</SYS>> Why does Harry use Felix Felicis in "Harry Potter and the Half-Blood Prince"? [/INST] To extract information from Professor Slughorn. </s>