Penetrate! (つらぬけ!) is a rush attack used by Goku. While the opponent is in the air, Goku charges and fires a one-handed Reverse Kamehameha at the ground to launch himself up into the air. Then, he shouts "I'm going to put everything I got into this punch!" and clenches his hand into an energy-powered fist. A silhouette of a Great Ape (which is said to represent Goku's hidden powers) appears as Goku puts his fist forward and punches through the opponent, inflicting a huge amount of damage.
Goku used this attack to defeat King Piccolo. After breaking Goku's legs and left arm, King Piccolo flew high up into the air and charged back down to kill the crippled Goku. However, with his right arm still intact, Goku launched himself up at King Piccolo with a Kamehameha and attacked him with the "Penetrate!" punch. Although King Piccolo braced for impact, the force of Goku's attack was too powerful and the evil Namekian was left with a large, gaping hole in his chest. However, King Piccolo spat out the egg of his final offspring and reincarnation and encouraged his son to avenge his death by killing Goku before succumbing to his injuries and blowing up.
Goku later used the "Penetrate!" punch when fighting Mr. Popo, but Mr. Popo effortlessly dodged it, much to Goku's surprise.
Appearances in games
"Penetrate!" was named in Dragon Ball Z: Budokai Tenkaichi 3, where it is Kid Goku's Ultimate Blast. It is named Super Dragon Fist in Dragon Ball Z: Budokai 3, Punch Through! in Dragon Ball: Advanced Adventure, and Pierce Strike! in Dragon Ball: Revenge of King Piccolo (Goku shouts "Pierce Strike!" while performing it in a the final cinematic). In Budokai 3, Goku launches the Reverse Kamehameha, then flies towards his opponent, pummeling through him, and with a tear in his eye, he says "I did it!" It is also used in Dragon Ball 3: Gokuden. The move reappears in Dragon Ball: Xenoverse, only being used by the Future Warrior. This golden version is used to attack Démigra, but fails to kill him as it was only Demigra's Mirage. The Future Warrior's version visually resembles the Ki Blast Thrust which the Future Warrior learns from Yamcha in the GT Pack 1 DLC.
Prior to his battle with King Piccolo, Goku uses a similar technique to destroy the Pirate Robot. He uses it again to destroy the Red Ribbon Army Battle Jacket which the recently self-promoted Commander Black pilots, resulting in Black's death. This attack is the same as Penetrate! but with two hands extended forward rather than one (probably since Goku had no usage of his other limbs at this point when fighting King Piccolo). When reflecting on the events of the Red Ribbon Army war, Master Roshi refers to it as Goku "using his head." Goku also uses a similar technique to defeat Major Metallitron in Dragon Ball: Mystical Adventure.
Goku performs a similar attack using Kaio-ken as an impulse both to kill Misokatsun in the movie Dragon Ball Z: The World's Strongest and to wound a giant Lord Slug in Dragon Ball Z: Lord Slug. Gohan also uses a technique nearly identical to Goku's Penetrate! attack to rip a hole in Garlic Jr.'s body followed by blasting him with a Masenko. However, since Garlic Jr. is immortal, the attack barely fazed the Makyan, as he was able to regenerate all types of wounds. Gohan and Krillin also use a similar attack to destroy some of the Cyclopian Guards in Dragon Ball Z: The Return of Cooler. Gohan's attack is called Body Destruction in the Dragon Ball Z Collectible Card Game.
Later, Goku uses a similar attack against the left arm of a Meta-Cooler, and after, Goku and Vegeta also use the same attack to destroy it. Goku uses another similar technique to destroy God Guardon in the OVA Dragon Ball Z: Plan to Eradicate the Saiyans. The techniques Dragon Fist and Super Dragon Fist are believed to have been derived from the Penetrate! technique. A certain time after, Goku transformed into Super Saiyan 3, he performs another powerful technique charging two energy spheres in his hands to penetrate and explode the body of Janemba. In Dragon Ball GT, Goku uses the Dragon Fist to defeat Super 17 in a similar fashion to the way he killed King Piccolo decades earlier (by ripping a hole through the chest). Although the "Penetrate!" punch was strong enough to cause King Piccolo to explode, Super 17 is able to survive the Dragon Fist, and it required three Kamehameha waves from Goku to finally finish the Super Android.