The Two-Star Dragon

The two-star dragon is polluting the entire area, so Pan steps in to stop him. She is much more powerful than the dragon, who is getting pounded. But Pan's attacks seem to do less and less, until the dragon is able to overpower her. Goku tries to transform into a Super Saiyan, but can't do it. The dragon explains that his pollution causes everything to be poisonous, which is why Pan's strength decreased, and why Goku can't power up. The dragon beats them up, and then throws them into the lake. Giru, who is unaffected by the poison, goes underwater and pulls them to an uninfected part of the lake. There is a spring here that is feeding in pure water from underground, and Goku blasts the hole, flooding the lake with clean water. With their powers rejuvenated, Goku and Pan destroy the dragon and recover the two-star ball. The cracks on the ball disappear.