Danny agrees to watch his crush Wendy's dog, but ends up putting the pooch in a kennel. When he gets the dog back, it's a robot! Meanwhile, Cathy is trying to come up with an "acceptable" project for an Earth science fair.

A popular new cheerleader invites everyone at school to her big party, except for the MBC kids. Cathy snags an invitation but is trapped with everyone else when the cheerleader turns into an alien intent on taking the entire school (students and building) hostage.

A demented alien with a "Santa complex" starts kidnapping Singletown kids (including Sam) and using them as elves in his "toy factory." Meanwhile, Mark and Danny have to work together planning the school's holiday party (to try and impress Wendy).

Sam tries to simultaneously run a school bake sale, and help Cathy babysit for a very hungry toddler, who turns out to be a "dangerous" eater alien. Danny and Chris, meanwhile, must compete against Mark's extravagant efforts to ruin their bake sale.

A new sewer tunnel threatens the MBC's secret ship which is buried in Cathy's backyard. Especially when it turns out the sewer workers are actually sticky aliens, hunting for the MBC. Meanwhile, Mr. Fuster leads a science field trip to explore the infrastructure of the city.

Little John inadvertently subjects the MBC to the effects of his truth ray, causing them to suffer strange physical effects whenever they lie. This complicates their efforts to subdue an intergalactic villain. Meanwhile, Danny gets an opportunity to work with Wendy on an assignment - "Life on Other Planets: Fact or Fiction." But his inability to lie causes big problems for him as well.

Cathy invites the star of an alien "nature show" to Earth so he can document the planet's wild creatures. But the only "creatures" the alien wants to film are humans - and he has an evil plan to make them all look extra "wild" and dangerous.

Cathy gets detention only to find that the teacher in charge is an evil alien! Chris, Sam, and Danny attempt to cause "trouble" and get detention as well to assist Cathy in defeating the Sticky teacher.

A catchy song by an alien rock band literally takes over students' minds (including Danny), and makes them unwittingly construct a doomsday device during a Battle of the Bands concert. The MBC must form their own band to enter the contest. Meanwhile, Cathy looks for the perfect birthday gift for her grandfather.

Feeling under appreciated, Chris accepts an intergalactic talent manager's offer to make him star but ends up attracting the wrath of a vicious, competing, alien talent agent. Meanwhile, Cathy gets the lead in the school play.

The MBC battles a race of ferocious, bug-sized aliens who are trying to chase all the humans out of Singletown. Meanwhile, Principal Rollins pays a visit to Cathy's house to meet with Mr. Smith and, surprisingly, they really hit it o

Mr. Smith entrusts the gang to protect the "forget me stone" - an ordinary looking rock that causes people to lose a wide range of memories. An evil morpher is out to get the stone in the hopes of erasing people's memories (and forgetting his crimes).

Each year Principal Rollins selects one student to act as "principal for the day" and this year it's Danny. Principal Danny gets totally carried away and it seems like the only one who thinks he's doing a good job is Wendy.

The MBC protects Cathy's mind-reading, alien cousin Elton from the Pincher Bots that want to capture him. In the process, Elton reads Danny's mind and accidentally reveals one of his most embarrassing secrets to the entire school.

The kids must take action when Mark mistakes Mr. Smith's universal communication device for his cellphone, and almost starts an intergalactic war with his rude remarks to the alien callers. Cathy, meanwhile, has discovered the Earth concept of phone gossip.

The MBC are charged with protecting an alien ruler who is a tiny flower, but Jeremy naively takes the plant as a gift for his secret crush (Cathy). Meanwhile, Sam gets addicted to Chris' video game.

Various things start disappearing around town, but nobody sees where they're going. By slowing down surveillance cameras, the MBC discovers that a "speed morpher" is stealing all of Singletown's technology. If he isn't stopped, the town will collapse into chaos - and the MBC kids will all lose their new part-time jobs.

While looking through some old MBC artifacts Chris inadvertently brings to life a statue of Addison Single that stands in front of the school. It turns out that Addison (thought to be the town founder) was actually an evil alien that was "statue-ized" by a colonial version of the MBC.

A group of bubblegum-like aliens come to earth to seek refuge from their planet (Bagumblia) which is suffering from global cooling. Their leader is angered when Danny inadvertently chews him and declares war on humanity, taking Mark as their hostage. The Baglumbians threaten to unleash their hideous mastication monster on Mark, and the MBC must leap into action to protect him.

The demands of the MBC force Danny to duck out of several "tough guy" challenges by a new kid at school (who turns out to be an alien intent on disrupting the MBC's teamwork). Meanwhile, Cathy runs for student council president.

The MBC goes up against Herpitilius, a giant frog from outer space. Herpitilius was originally an earth frog who nearly got cooked up in a French restaurant, but managed to escape. He was abducted by aliens and turned into a super frog, and now he's returned to round up his earth brethren and exact his revenge.

The MBC encounters a weird-looking alien, Mimi, who seems to get everything ready for a wedding in Singletown.

The MBC embarks on a camping trip to search for a rare alien plant that only blooms once every 200 years and will provide fuel for their MBV. The MBC struggles to survive Mr. Smith's bizarre idea of a camping trip. While in the woods, they also discover an evil alien who's searching for the same flower.

When an alien named Doodo mistakes Chris for an intergalactic Emperor, Chris goes along with it, thinking it will be fun. But things quickly get out of hand when the MBC discovers that there is an evil alien named Krungnar who is out to mandelbark the emperor's flaggins.

When Danny and Sam mess up a few assignments, the IGA commander sends down two droids to assist the MBC. But, while Chris and Cathy get along with the new recruits, Danny and Sam suspect that they're up to no good. Meanwhile, Mr. Smith recruits the MBC to help him plan Cathy's "Sweet 250" birthday party.