Une transformation providentielle

Goku and Super Android 17 begin to fight. The battle is clearly in 17's favor, as Gero and Myuu programmed knowledge of all of Goku's techniques and abilities into him; however, Goku transforms into Super Saiyan 4, which neither Gero or Myuu knew about. He hits 17 with hundreds of energy blasts, but none of them seem to hurt the android. He tries a Kamehameha wave, but 17 makes no effort to get out of the way, and Goku realizes that 17 is absorbing the energy, just like Android 19 did, but without the devices on the hands. Super Android 17 has now absorbed so much energy that he is stronger than Goku. Goku tries to use Instant Transmission to sneak up on 17, but the android can sense where he is going to appear by analyzing the distortion Instant Transmission causes in the atmosphere. With none of Goku's tactics working, Super Android 17 conjures a powerful energy ball to finish him off. (Source: Wikipedia)