From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
Vegeta draws his hands back and gathers up all of his ki. He then thrusts his palms forward and discharges a massive golden-yellow beam of energy at his opponent.
Dragon Ball Z
Vegeta used this attack in his fight against Cell in his Perfect form. Though Perfect Cell was significantly more powerful, the sheer amount of energy that Vegeta put into the attack, reflected by significant charge time, nearly obliterated the overconfident Perfect Cell as well as the entire Planet Earth. Sensing the danger only at the last second, Perfect Cell attempted to dodge the beam as the destructive energy disintegrated the ground on which he stood and continued off into deep space. When the dust cleared, Perfect Cell had lost half of his upper torso (he was also shocked that the attack was actually able to damage him). Despite this, and to Vegeta's surprise, Perfect Cell was able to regenerate himself and continue the fight.
Prior to his battle with Perfect Cell, Vegeta used a similar attack in his battle against ReaCoom on Planet Namek. The charge time was significantly shorter, however, and resulted in a weaker attack. The posing for the attack was nearly identical to Vegeta's Final Flash as an Ascended Super Saiyan, the only difference being that Vegeta's fingers were splayed straight out when he thrusted his hands forward instead of being bent forward. The attack also had a blue color instead of yellow like the initial attack. Recoome's armor was mostly obliterated by the blast, though he emerged from the dust undamaged and even striked a pose.
In the anime (but not in the manga), Vegeta used the Final Flash against a Cell Jr. he was fighting, but the attack was easily dispatched. In this instance, Vegeta spent only a few seconds charging up the attack rather than the several minutes used against Perfect Cell (presumably due to the desperate situation at hand). This could explain why the Cell Jr. managed to effortlessly deflect an attack that Perfect Cell himself was previously vulnerable to defend from.
Vegeta later used it against Super Saiyan 2 Goku as Majin Vegeta (the attack name is heard, but not seen, as he placed the fingers of his hands upward instead of the heels of his hands to each other).
Vegeta later used the Final Flash against a swarm of Kid Boos while buying time for Goku to charge his Genki Dama. Goku also used a very similar move against Kid Boo while fighting in his Super Saiyan 2 form in an anime filler sequence.
Dragon Ball GT
Baby also used the Final Flash twice in his battle against Oob. He previously used it against Goku on Earth, but Goku avoided it.
Final Flash appeared in Dragon Ball Z Gaiden: Saiya-jin Zetsumetsu Keikaku.
- It should be noted that in the anime the attack's color matches Vegeta's default aura, but this is not true in Dragon Ball Z Gaiden: Saiya-jin Zetsumetsu Keikaku where Super Saiyan Vegeta uses a blue Final Flash against Dr. Raichi and Hatchiyack.
- When Vegeta uses the Final Flash against Hatchiyack in Gaiden: Saiya-jin Zetsumetsu Keikaku, he is shown charging it normally. When he fires it, however, he does it with one hand (in a similar manner to the Maximum Flasher). This is most likely a mistake made by the animators.
- The Final Flash is often seen in Vegeta's repertoire in the Dragon Ball Z video games, often as one of his strongest attacks, if not the very strongest. It also comes in a blue color like the Kamehameha in Dragon Ball GT: Final Bout.
- Vegeta Baby shouts, "Big Bang Attack!" when he uses this attack in Dragon Ball GT in order to confuse Goku. He does the same thing when he uses the attack in the Budokai Tenkaichi video game series.
- Gogeta is able to use the Final Flash in the Raging Blast video game series and Dragon Ball Z: Ultimate Tenkaichi, however, it is colored a white-ish blue like the Kamehameha.