Mega Flare, Sun Flare and MegaNuke, is a recurring attack in the Final Fantasy series. It is normally a very damaging move used by the summon Bahamut. It is an upgraded version of the spell Flare, and deals heavy non-elemental magic damage to all targets. Megaflare sometimes has an even more powerful version called Gigaflare, and occasionally Bahamut is able to use other versions of Megaflare with different prefixes.
It's a attack that Bahamut is known to use in a lot of Final Fantasy so don't think so.