Instructions
Circle the Blast-Ended Skrewts and dodge their attacks until you are up against a wall at some distance from them. They move fairly quickly, so try to get a feel for how they move and time your dodges well.
Wait for the Blast-Ended Skrewts to start charging toward you. Dodge their attack at the last moment so that they crash into the wall behind you. They will be stunned for a few moments.
Run around to the other side of the Blast-Ended Skrewts so you are standing behind them. Attack them from behind with any of your jinxes until they get back up. Repeat the attack pattern until they are destroyed.