"Now you will know the horror, Frieza!"
Now I'm Mad! (オレは怒ったぞ！ Ore wa okotta zo!) is a Power Up technique used by Goku in his Super Saiyan and Super Saiyan Blue forms. The name for this technique is based on the dialogue Goku used against Frieza.
Super Saiyan Goku shouts "I'm Angry" as he powers up. The technique causes him to be at full power with his attributes increased for a short period of time. In addition to powering up the user, they will also injure the opponent if he or she is in close proximity by simply using the ability.
Goku utilizes this shortly after first becoming a Super Saiyan when about to assault Frieza on Namek for his murder of Krillin, and later again in the same battle when Frieza not only taunts Goku by referencing his murder of Krillin, but also referred to him merely as "that Earthling".
"You took my body, you took my life... Then you even killed Chi-Chi and Goten... You're gonna regret telling me that, Zamasu! Cause now I'm mad... I'm really, REALLY mad..! And now it's time... TO PAAAAAYYYYYY!!"
— Super Saiyan Blue Goku using the power-up after learning Goku Black killed his family
In Dragon Ball Super, when Goku Black informs Goku of how he stole Goku's body and Chi-Chi and Goten were murdered by him in his timeline, this caused Goku's anger to power him up. The power-up allowed Super Saiyan Blue Goku to overpower both Goku Black and Future Zamasu. However, once Goku stopped his assault, it gave Black enough time to heal and power-up himself to defeat Goku with his newfound Divine Lasso.
Video Game Appearances
Now I'm Mad! was named and appears as a Blast 1 used by Goku (Mid) in his Super Saiyan form in Dragon Ball Z: Budokai Tenkaichi 3; it uses three Blast Gauges. The technique reappears as one of Super Saiyan Goku's Super Attacks in the Raging Blast series, under the name Now I'm Angry!. The move reappears as an equipable Z-Soul in Dragon Ball Xenoverse. The Z-Soul raises health by two stages and grants free skill use for a short time whenever an ally is knocked out. Super Saiyan Goku also uses it in cutscenes after transforming in Age 762 in both Xenoverse and Dragon Ball Xenoverse 2.