While visiting Washington, D.C., Ben confronts Dr. Animo, a disgruntled scientist whose Transmodulator can mutate living animals, and even resurrect dead ones, and eventually learns a lesson about what being a hero really means.

When Ben and Max go on a fishing trip with Captain Shaw, they encounter the Krakken that lives in the lake. With Gwen’s help, they find out that the creature is upset because Jonah Melville, a poacher pretending to be an animal lover, is stealing its eggs.

Ben and Max drive to a retirement center to visit their Aunt Vera, but find out that evil shapeshifting aliens called the Limax are kidnapping the residents to eat them later and taking their form to replace them.

While in a tourist trap town called Sparksville[disambiguation needed], Ben plays a practical joke that accidentally unleashes Megawatts, small electric creatures. Ben must stop them from multiplying out of control and destroying the town, and turns into Heatblast to seal the Megawatts in a large fishbowl.

While visiting a travelling circus, Ben fights an evil clown named Zombozo who is draining people’s souls through their laughter. Conquering his own fear of clowns, Ben defeats Zombozo by terrifying him as Ghostfreak, and saves his family. Ben admits that he scares himself while fighting as Ghostfreak.

During a trip to New Orleans, Ben prevents a powerful sorcerer named Hex from stealing the Arkamada Book of Spells. During the fight Ben obtains one of Hex’s five magical Charms of Bezel and gives it to Gwen, giving her the supernatural ability of luck manipulation. Using a Mardi Gras costume, Gwen becomes a superheroine […]

In a fit of stubbornness, the Omnitrix transforms Ben into Grey Matter and leaves him stuck in that form for longer than normal. During this time, he is captured by Howell Wayneright, an alien-obsessed nerd whom then gets himself and Gray Matter captured by a secret society of knights known as the Forever Knights. The […]

Clancy, a man who can control insects, wants to take revenge on Councilwoman Liang because she wants to tear down the building where he and his insects live. Meanwhile Ben has to deal with the strange side effects a cold has on his alien forms: Wildmutt is unable to see or smell, Four Arms smells […]

During a trip to Yellowstone National Park, Ben discovers the eleventh alien on the Omnitrix, Cannonbolt. At the same time, a meteor crashes nearby unleashing a giant, tick-like alien called the “Great One” that intends to devour Earth. Ben easily defeats the worshippers, but the Great One turns out to be impervious to the original […]

When Sixsix and his new partner Vulkanus arrive in Pittsburgh in search of raw minerals to build a devastating bomb, Ben joins a group of alien super heroes, the Galactic Enforcers, to stop them. However, all is not well with the new group, as a small gift of Ben’s chocolate weakens the group’s leader, Ultimos, […]

Distracted by Ben and Gwen quarreling, Max almost hits a young camper named Gilbert on the road. They take the boy back to his camp, Camp Opinicon, only to find no one there. As they investigate the premises, they find two more children, twins named Andy and Mandy, who are hiding from something that caused […]

Max’s Plumber equipment detects that an ancient mask had been unearthed in Texas. This quickly triggers a change in Max’s attitude; he claims that this artifact would lead to the most powerful weapon ever designed, and that he should retrieve it before it falls into the wrong hands. Max immediately becomes more impatient, worse-tempered, and […]

The family ride a jet belonging to Grandpa Max’s old friend, Donovan GrandSmith, who owns an underwater resort in the Bermuda Triangle. At the entrance, they receive a warm welcome from Donovan himself, though they also meet with his grandson, Eddie, who doesn’t seem to be excited about their guests. When Eddie, Ben, and Gwen […]

Ben has been having strange nightmares about Ghostfreak. During a tour of an academy school Gwen wishes to attend, Ben sees and hears Ghostfreak everywhere. When Frightwig, Acid Breath, and Thumbskull show up, Ben activates his Omnitrix; however, it transforms him into Ghostfreak. After a vicious battle, Ghostfreak escapes from the Omnitrix. Ghostfreak removes his […]

When Ben tries to take apart the Omnitrix to see how it works, he ends up breaking off its face and causing weird combinations of his alien forms when he transforms. Additionally, the broken piece begins mutating the smaller creatures it comes into contact with. Meanwhile, Dr. Animo escapes from prison and, during a battle […]

As Ben and Gwen are planning Max’s birthday on the shore of Horse Thief Lake, a mysterious stranger appears and kidnaps her, so Ben follows her into a strange portal. When the dust settles, Ben suddenly realizes he is twenty years old in the future, where humans and aliens live peacefully. Ben then learns that […]

While visiting the Mega-mall-opolis in Bloomington, Minnesota, Ben and Gwen watch a hypnotist perform. Gwen volunteers Ben as a test subject, and the host, Sublimino, successfully hypnotizes him. When asked to act like an alien, Ben naturally turns to the Omnitrix and almost changes in front of the audience. Even though he is stopped by […]

The Tennysons come upon a bizarre Christmas village in Death Valley, run by a Christmas-obsessed man (Mr. Jingles), who thinks Grandpa Max is Santa Claus and proceeds to trap him. As Ben and Gwen explore, they learn about a strange curse on the village, in which the village was frozen at Christmas, in the 1930s […]

During a visit to a Navajo village in New Mexico, owned by Max’s old Plumber partner Wes Green, Ben falls in love with Wes’ granddaughter Kai, while a wolf-like creature appears in a flash of purple lightning. Wes believes it to be a Yenaldooshi, or Navajo werewolf. It stole and ripped the receiver. Wildvine fights […]

Ben and Gwen are playing the Sumo Slammer video game and Gwen is beating Ben at it. Ben turns into Upgrade and merges with the computer so he can lower Gwen’s score. As Gwen tries to get Ben out, lightning hits the van and zaps them both into the game. They realize that all of […]

When a television show called Super Alien Hero Buddy Adventures shows up, Ben gets angry and demands credit since it stars cartoon versions of Fourarms, Heatblast, and Wildmutt. Furthermore, it has replaced his favorite show, Kangaroo Commando. It just so happens Ben and Gwen are visiting Planetary Studios in Hollywood at the time, so he […]