Expecto Patronum

An incantation of your innermost positive emotions bursts forth in a bright explosion of light from your wand, pushing back creatures of evil, such as dementors. The spell usually takes the form of a burst of light, but with sufficient positive emotions, it can also take the form of a spirit animal. a patronus, unique to you only. Furthermore, with one hundred percent of your positive energy poured forth into the spell, it explodes in a 300 ft sphere of pulsing magical light emanating from your patronus. Your DM determines the form that your patronus takes. Your patronus can also be used to travel long distances and deliver messages in your voice.