Supernova inflicts a large amount of non-elemental magic damage on all of target party for 70 MP. It is a Blue Bullet spell that can be learned while wearing the Gun Mage dressphere and can be learned from the Ultima Weapon.
Supernova is also used by Proto-Ultima at Dun Scaith. This attack is used at the late stages, initially inflicting heave damage on the alliances. He then begins charging energy from Aetheric Condensers, for a more powerful Supernova with a one minute countdown. If the alliance does not break the condensers and defeat Proto-Ultima before the countdown finishes Supernova, it will wipe out the entire alliance.
Supernova also appeared as Proto Ultima's special attack in the 2016 North American Fanfest secret trial. Similar to Ultima Weapon's Ultima ability, it will cast Supernova as an enrage ability when it is low on health and the party must defeat it before the spell instantly kills the entire alliance.