The episode begins where we meet up with Ben making faces at another kid in another car. They trade silly, stretched-out faces towards each other, including random tongue flapping. Gwen comes along and makes fun of Ben’s faces, although she says that it would be an improvement if his face were to become stuck like that. The kid in the other car then decides to eat his hamburger and shows it all chewed up to Ben, and Ben refers it as the “seafood special.” Ben decides to beat his game by ducking under the table to activate the Omnitrix. He then comes back up as Stinkfly and spreads slime all over the RV window. Instead of continuing the game, the kid is frightened by Stinkfly, as well as his own father, who notices Ben. The kid’s father floors it to get away as fast as possible. Ben is unbelievable amused by his own joke, and rolls around the floor laughing while Gwen chides Ben for taking the prank too far. She then sits down, and Stinkfly sprays slime onto her seat. He says that going too far is impossible, because he claims that funny is just funny. Up front, Grandpa Max notices a situation outside and he tells Ben to come up front. Grandpa Max hits the brakes, and Stinkfly slides to the front. On the road ahead of them, a propane truck has overturned, and the truck driver is stuck inside. To make it worse, a fire is spreading. Grandpa Max explains that the truck will be a “rocket to the moon,” once it is ignited by the fire.
Stinkfly notices that the flames are too hot to get close and wished that he were Heatblast instead. However, he must use what he has now, and Ben gets an idea. He flies above the wreck, and uses his slime to put out the fire. He then goes on top of the truck and uses his sharp tail to tear the metal off the roof. Ben creates a hole big enough to get the truck driver out, who was screaming until he is back on the ground. Stinkfly says that mucus saves lives, yet the kid from earlier is there. He points out that he is the one who “ate” Ben from earlier. Stinkfly excuses himself and leaves the site before people starts asking him questions.
They continue along the road, and Grandpa Max has a plan for the kids. Gwen notices a sign that reads, “You’ll have a ball with it.” Ben asks Grandpa Max where they’re headed, but he seems to be making it a surprise for them. They finally arrive at their destination, and once they got off the RV, they learn that they are visiting a place called Sparksville, a town that is nothing but exhibits for tourists. The mayor shows up to greet them in a monotonous voice, although it seems that he is an amusement park operator rather than a town mayor. Grandpa Max gives Ben and Gwen their tickets and heads to the motel to check in.
With nothing better to do, the kids decide to go around and start seeing the exhibits. They first visit the jackalope, and the mayor is there, who doubles as the ticket collector. Ben questions him in what he thought he was the mayor, but he replies that he wears the crown and is burdened by many hats. They enter the building, and the mayor makes sure to tell them to mind the signs. Inside, they take pictures of everything, making funny faces as they capture the moments. They take pictures of several different places, including: the front of the jackalope building, an “American Gothic” painting cutout, a planetarium in which an employee is replacing the “sunlight” bulb, a giant house of cards, a giant hot-dog, Ben getting sprayed with ketchup and mustard, Gwen getting a hot-dog tossed at her, Ben wearing jackalope horns and Gwen wearing googly-eye glasses, the world’s largest fish bowl, them sitting on a bench bored, and an “It is this way” sign.
They decide to finish up their day to see the barn containing “It,” and the mayor says that it is the weirdest and wildest thing to ever reach Sparksville. They enter, and different warning signs are shown along the way to it, which each one forbidding any touching, taking pictures, or using electrical devices near it. After all that, they learn that it is just a giant rubber-band ball. The mayor walks up to ponder on what may be inside the giant ball. Ben is skeptical, and he says that it is more than a giant rubber-band ball. The mayor says that they can stay as long as they want, but he recaps to them to mind the signs. Ben and Gwen are annoyed by the rules. So Ben decides to have a little fun and he runs behind the ball to activate the Omnitrix. He picks up the ball as Four Arms, and starts playing with it. Gwen is actually with him this time, laughing at all the various jokes he makes with the ball. Four Arms tosses it from one hand to another, and Gwen warns him to be careful, otherwise he might drop it. Ben though ignored her statement and became confident that he can lift it with one hand, but ends up losing his grip and drops it. Gwen gets out of the way as the ball bounces off the floor and through the roof.
The ball continues to bounce after it left the barn, it knocks over several exhibits and crushes a food cart, and Four Arms was able to slow the ball down, though it knocked over the house of cards before it stopped completely. Gwen smacks Four Arms for ignoring her warning. Ben claims that he can put everything back, but he reverts back to a human. He leans against the giant ball and contemplates the situation, while a small charge from the Omnitrix is drawn into the ball.
At the motel, they work out what they will say to Grandpa Max. Ben says that they should play dumb and not say a word about what they did, though Gwen says that Ben is more experienced at it. Inside the motel room, it appears that the entire room has been turned on its side, including the beds and the door. Grandpa Max comes in to ask how their day went, and Gwen immediately shifted her behavior to be evasive at what just happened. Ben covers her by saying that they had a great time, and he can’t wait to check out their bathroom.
Back at the rubber-band ball, the charge has spread all over the surface. A small electric bolt escapes from it and starts to circle the power lines and exhibits. It then puts a hole through the welcome sign for the town. The bolt then reveals itself to what appears to be a yellow creature. A plus and a minus are on its back, much like a battery, and a lightning bolt is on its chest. Electrical charges can be seen from inside a hole on its head. It is amused by its work, and laughs and takes off.
Ben and Gwen are sleeping, and Grandpa Max remarks that there is something out of place, and wakes them up and causing them to literally fall out of the sideway beds. Gwen immediately assumes that they are in trouble. Ben tells her to continue lying about the incident. Grandpa Max then calls out Benjamin and Gwendolyn, which continues to put more stress onto Gwen.
Outside, the entire place has been trashed, far more than what Ben had caused much earlier. Grandpa Max comments that it looks like a tornado hit the place, and Ben thinks it’s a good thing. Grandpa Max then sparks up his suspicions, but Gwen helps to get rid of them. The mayor comes by to say that he knows who did it, and Grandpa Max opens up his suspicions towards them again. The mayor says that something else did it, which them removed Grandpa Max’s suspicions. Grandpa Max asks him who did it, and the little energy creature appears. It hangs around Ben and Gwen, making silly poses and faces, and pulls Gwen’s shirt over her head. It leaves, and the mayor says that it is a Megawhatt. He says that no one knows where he came from, yet it is living lightning that runs amok. They are normally trapped inside the rubber ball. Gwen says that it might be an alien, but the mayor says that it is just crazy talk.
Near a soda machine, the Megawhatt sees the chance to cause even more trouble. It enters the machine and causes it to fire soda cans. Ben, Gwen, and Grandpa Max dodge the cans, while the mayor continues his explanations, seemingly to be unconcerned of his safety. He says that Megawhatts feeds on electricity, making them more powerful. They also have a dangerous sense of humor. The barrage continues, and the four takes cover from a nearby overturned car. Grandpa Max asks why they would keep such a dangerous object, the mayor says that it would be better if people minded the signs, and Grandpa Max confirms his suspicions to Gwen and Ben. Grandpa Max decides to deal with the problem later, and he asks the mayor how they’ll stop the Megawhatts, though he says that they are the ones who released it, so they need to be the ones to catch it.
The three start looking for the Megawhatt. As they discuss where they might possibly find it, it sneaks up behind Grandpa Max and gives him a wedgie, literally lifting him off the ground. Grandpa Max doesn’t find the pain funny. Ben, in response, activates the Omnitrix and becomes Upgrade. Gwen questions Ben why he became Upgrade, though he only answers that it was a complicated decision. She then pointed out the watch did not let him become the alien he wanted to be.
The Megawhatt lets go of Grandpa Max, and continues to cause havoc on the other exhibits. He makes the world’s largest ketchup bottle to overflow. The top of the bottle then cuts the head off a fake giant chicken. Upgrade rolls up on the rubber ball, and he sends pieces of rubber-band flying in every direction, which causes even more damage. Gwen yells at him, yet the mayor is unintentionally calm, watching all of what is going on. Megawhatts laughs at the damage Upgrade has done, and he fires a positronic blast. It dodges the blast, yet Upgrade is happy to find the new power, which threatened the Megawhatt. It continues to laugh and takes off.
Upgrade chases the Megawhatt, though it proves to be too fast to hit. It stops to make fun of Upgrade, Ben manages to grab it, though ends up being electrocuted. Gwen and Grandpa Max watch, Grandpa Max wonders how to stop the Megawhatt. Upgrade is getting tired of chasing it, and tosses a sewer lid at it. The lid cuts the Megawhatt right in half, though it regenerated into two separate Megawhatt. Upgrade mulls on his less-effective action, and then reverts back to human form. At that moment, Grandpa Max drives a truck carrying the world’s largest thermometer and picks Ben up. The Megawhatts chase him, though they used the thermometer as a ground. The mayor by to a point that the ground the merely a conductor, and they little creatures will find their way back to the surface. Sure enough, they start to come from every power line and telephone line.
The Megawhatts gained a massive amount of energy, and continue to destroy the place. They take the wheels off every car, a transformer, a fire hydrant, and then the world’s largest toothpicks. The toothpicks fall, and everyone runs for cover. The mayor shows his regard to his safety again, sitting on a bench eating popcorn.
The Megawhatts settle on the knocked over jackalope near the motel. After speaking to each other in some incomprehensible language, they take off, and take over the planetarium exhibit, which then walks itself off. Grandpa Max decides to follow it in the RV. He finds that the Megawhatts have gotten to it, and wrote “U AM LAME” on the side, as well as smiley faces drawn all over it. The mayor then says that the Megawhatts are probably headed to the hydroelectric dam to power up, and then use it to cause trouble in other towns. Gwen looks up and sees the world’s largest fish bowl, which then gives both of them an idea.
At the dam, the planetarium is busy trying to smash through the dam. A column of flame then engulfs it. It looks up to see Heatblast on top of the dam. Heatblast threatens it, and the planetarium hits the dam again, causing a leak and knocking off Heatblast over the edge at the same time. Heatblast descends the dam to the rapidly approaching water, though he was able to create a column of flame under himself to ride it to safety. He is surprised to have learned yet another new ability. He moves to seal the leak, while the planetarium moves to the turbines absorbing the energy.
Near the turbines, a large tarp covering a sphere-shaped object can be seen. As the giant planetarium approaches the turbines, Heatblast arrives, riding another column of fire. He still needs to get the hang of controlling it though, as it goes out and causes him to crash into a nearby wall. He staggers out, though the planetarium punches him across the dam. Gwen sneaks up behind it and sprays it with a hose to annoy it. As they try to punch her, Heatblast makes a large fireball, and he was just in time to throw it and smash the structure into rubble. The Megawhatts leave it, and Heatblast taunts them to attack back. They try to get him, though he disappears in a cloud of smoke. Heat Blast then reappears nearby the tarp, and blows kisses at them. They become so annoyed and attacked recklessly towards him as he enters the tarp. They follow him in, Grandpa Max shows up to pull the tarp off, which revealed the giant bowl to be filled with the Megawhatts inside. Heat Blast finishes it up by melting the top to seal them in. Heatblast taunts them, and Gwen states that science saved the day. Ben reverts back to a human, and made it more specific that science-fiction helped.
Back at the town, the mayor thanks them for their work in capturing the Megawhatts. Grandpa Max apologies for any problems and setbacks they might have caused, yet the mayor turned their efforts into progress by turning the Megawhatts’ prison into a giant light bulb. He says that everything will be all right, if the people mind the signs. The sign states, “In case of emergency, do not break glass.” They head back to the RV, and Ben says that he is pranked out. Grandpa Max says that there are a time and place for jokes. Ben opens the door to the RV, and a bucket of water falls on top of his head. Grandpa Max then adds on to his previous statement by saying, “Funny is funny, especially when it’s not on you.” Gwen and Grandpa Max laugh at Ben, and the episode ends on that note.