What could possibly go wrong with a swimming pool entirely filled with jiggly, bouncy gelatin? For stepbrothers Phineas and Ferb, it sounds like the perfect start to an amazing summer day. But things take a wild turn when the bumbling evil scientist Dr. Doofenshmirtz accidentally unleashes his latest wacky invention. His wild contraption zaps the pool, bringing the massive, wobbly dessert to life! Suddenly, the boys are facing down a giant gelatin monster that is on the loose and causing chaos. When their older sister Candace gets caught in the gooey mess, it is up to Phineas and Ferb to save her. You will have to dive right into the action as the boys race against time to stop the squishy beast before it ruins their backyard fun forever.