Jackie's Shocking Secret (悟空最大のピンチ!! Gokū Saidai no Pinchi!!, lit. "Goku's Greatest Pinch!!") is the fiftieth chapter of the Dragon Ball manga. The chapter's anime counterpart is the first half of the episode "Number One Under the Moon?"
Jackie Chun decides he has no choice but to use "that move." Although, he doubts Goku would die from it. Jackie Chun states the move he is about to perform was has only been performed on a human being once before, Grandpa Gohan. This shocks Goku, knowing Jackie Chun fought with his grandfather. Jackie Chun claps his hands together and powers up for the attack. After a few moments, his hand begin to emit electricity. Then, Jackie Chun fires electricity out of his hands to Goku, which lifts Goku in the air. Yamcha tells Krillin that this is the Thunder Shock Surprise, which uses energy as 20,000 volts of electricity. Jackie Chun tells Goku to give up, seeing as even Grandpa Gohan could only make it this far. Goku says "I...Give...", but suddenly, he sees the Moon. His eyes turn red as he transforms into a Great Ape.