Heat Dome Attack (ヒートドームアタック) is an energy wavetechnique that is Future Trunks' most powerful attack in his Super Saiyan form.
First, Future Trunks throws his opponent up in the air and points both his hands up in the air. Then, he charges a large dome of yellow energy around himself. From this energy dome expels a gigantic Finish Buster up at the opponent, inflicting an enormous amount of damage.
Future Trunks uses this attack to destroy Future Cell in his imperfect form in his alternate timeline. Thanks to his training from the present timeline, Future Trunks easily outclasses Future Cell and knocks the Androiddown into the ground. When Future Cell attempts to attack with his tail, Future Trunks catches it and throws Future Cell up into the air. Future Cell then prepares a Kamehameha in hopes of defeating Future Trunks, but Future Trunks counters and destroys Future Cell with the Heat Dome Attack before he could fire his Kamehameha, declaring that the nightmare is over. With the Androids defeated and peace finally restored in his timeline, Future Trunks thanks Goku and the others for everything they have done for him. Future Trunks also uses this attack to destroy Future Dabura and Future Babidi to prevent them from awakening Future Majin Buu.
Later in the series it is shown when Future Trunks fights Future Dabura and Future Babidi, he uses a similar technique to the Heat Dome Attack.