1. Difficult for the caster to control
2. It will pursue any nearby lifeforms and anything that it can destroy,
3. one of the few substances known to be able to destroy a horcrux.

an immensely powerful fire that cannot be extinguished by normal or enchanted water,[1] It is also very difficult for the caster to control,When cast, the fire appears with a roaring, billowing noise and gives its victims only a split-second's warning to escape, quickly consuming anything in the vicinity of its caster.[1] The flames are of abnormally large size and take the shape of fiery monsters and beasts such as snakes, dragons, eagles and chimaeras, constantly mutating into other beasts as well as powerful, formless flames that destroy all things flammable around it.