Chill for a Day — Aaron Rosenberg

When Ben gets stuck in an Ultimate Alien form, chaos breaks loose!

When Ben as the Ultimate Big Chill decides to take on a mysterious alien alone one night, the alien throws chemicals at him and gets away. The Ultimate Big Chill tries to transform back into Ben, but he can't-he's stuck! With a looming chemistry test and a strange alien to catch, Ben can't take a day off. He has to go to school in alien form to take his test and look for the alien between classes. Luckily, the alien turns out to be a good guy who just needed a sample of Earth water and Ben is able to change back by using some other chemicals!