Atomic Blast (or Final Impact) is a fierce bolt of energy that Majin Vegeta fires from his index and middle finger. He first used it to kill a Saibaman for not being able to defeat Tenshinhan. He also used it to kill Kiwi who was fleeing from him. Vegeta later uses it to blow a hole right through Majin Buu, but the pink monster was able to regenerate.
This attack is featured in various DBZ video games as one of Majin Vegeta's signature attacks (the other being the Final Explosion suicide technique).
In the Budokai series, this attack is called the Atomic Blast.
In the Budokai Tenkaichi series, this attack is called Final Impact.Also in Dragon Ball Z: Supersonic Warriors 2, Majin Vegeta uses a variation of this attack called Atomic Burst in which he fires a large blast which "bursts" into 5 bolts of energy.