"Get out of here!" Bertrand yelled, slipping a vial out of his jacket and, checking the color, lobbed it into the oncoming phalanx of Dementors that were swooping towards us. A skeletal Dementor hand slashed at the vial, hoping to knock it away. The small vial exploded into a large ball of fire, and the mass of Dementors that were clustered together caught on fire and screamed as they burned and dissolved in the sun.