While shopping at an ice cream store in the desert, robbers attempt to steal an ATM. Ben and Grandpa Max capture the villains, but this is only the lesser of their problems. Then they drive to a retirement center to visit Aunt Vera for the weekend, but something very strange is happening here. Ben finds out that there is an evil species of alien shape-shifters taking over the retirement center for food. How will Ben save the day from robbers, strange aliens, and cheek-pinching aunts?

After having a gross-out contest with the kid in the car next to him, Ben finds a propane truck tipped over, about to catch fire and cause a huge blast. With that taken care of, Ben and the gang are off to Sparksville, a town which brings new meaning to the words "tourist trap." After exploring all of Sparksville's many attractions, Ben and Gwen head over to see "it," Sparksville's main attraction. When they finally see "it," they are thoroughly disappointed and decide to pull a little prank. After Ben turns into Four Arms, he looses control and sends "it" flying and destroying the town. Ben says he will move it back, but the Omnitrix powers down and Ben accidentally unleashes Megawhatt, a small little alien with a big sense of humor. Now, Ben must stop this creature from destroying Sparksville.