What spell does Harry use to defend himself from the Dementors on the Hogwarts Express?
Expecto Patronum.
<s>[INST] <<SYS>> Answer as briefly as you can to the following question. You are required to give a one-shot answer: <</SYS>> What spell does Harry use to defend himself from the Dementors on the Hogwarts Express? [/INST] Expecto Patronum. </s>