"Now you will know the horror, 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. 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. He later uses the ability shortly after becoming a Super Saiyan when fighting Cooler on Earth, with Cooler noticeably being knocked back simply by his use of the ability, implying that the ability, in addition to powering up the user, will also injure the opponent if he or she is in close proximity.
Appearances in games
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 games, 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.