Insectiva tries to destroy the city using giant, mutated termites.

A bitter sewer worker merges with a slime mold and turns into a monster who attempts to smother the surface dwellers in slime. Meanwhile, Ty tries to get more people to eat at the cafeteria.

The villain, Fartor wreaks havoc and seeks revenge on his cruel brother by causing a fart epidemic in order to fuel a giant robot called Fartzilla.

Sloppy Joe, the world's dirtiest bad-guy, takes all the worst smells in the world and makes a giant stink bomb. Meanwhile Ty asks Naomi out on a date.

A former beauty queen, calling herself the "Scab Fairy", invents a weapon that allows her to steal people's scabs so that she can inflict them on others.

Lance Boil builds an infrasound ray gun that causes instant diarrhea, thereby severely hindering any police investigation.

Insectiva has created a strain of giant mind-controlling head lice that grow on all the kids' heads at Ringworm High, converting them to zombies.

Mutant hagfish attack the town. Ty and Abby follow their slimy trail of destruction. Meanwhile Ty and Abby get a pet kitten named Hairball.

A crazed basketball player creates a plague-like Athlete's Foot epidemic using his new brand of popular running shoes.

A giant Owl terrorizes the people of town and especially its pigeons. Meanwhile, Lab Rat refuses to come out of the Gag Lab because of his fear of the outside world.

An attack on the city's water system makes people sick.

Ty and Lab Rat design a vehicle that crawls and leaps like an insect, and then are challenged to a race by Insectiva.

A boy causes organic things to rot just by touching them, so Abby and Ty try to cure him.

Lance Boil shrinks himself and tricks Ty into drinking him so he can tinker with Ty's brain once inside his body.

Instectiva, Lance Boil and Sloppy Joe inflict the members of the Bureau of Grossology with parasites, halitosis and acne in an effort to take over the city.

While defusing a device Lance Boil planted in town, Abby gets hit by a ray that instantly starts aging her at 6000 times the normal rate.

Competing in the school Science Fair, Ty's main rival is Patrick and his cool robot. Deciding to jazz up his fruit-fly project with a little mutagenic kickstart, things go wrong almost immediately.

A mad proctologist, Dr. Colon, breeds a giant intestine that he intends to snake around the world, unless Ty, Abby, Paige and Naomi can stop him.

When people start showing up with bite marks on their necks, Ty and Abby suspect vampires. But when they dig a little deeper, they discover that it's another kind of bloodsucker that's causing trouble – leeches! Worse, Abby is deathly afraid of these hungry invertebrates.

Gassy super villain Fartor returns with a scheme to fart-up the entire planet! But with a plan this big he needs help, and he's got his sights set on Ty.

Fartor and his new apprentice, Far-Ty join forces to drill into the planet core and turn the earth into one big gas planet. It is up to Abby to stop the gassy bad-guy and re-convert Ty back to an oxygen-breathing Grossologist.

Kid Rot returns and his powers are out of control. The forest is rotting, and Kid Rot is behind the destruction! Will Abby and Ty stop his rotting tide of evil before he destroys the planet?

A new nocturnal villain, Darko Crevasse, plunges the city into darkness with the help of his army of creatures of the night. Ty scrambles to shed some light on the problem before it's lights out for everyone.

Sloppy Joe creates a friend out of stolen boogers.

Abby is kidnapped and placed in a greenhouse filled with man-eating plants.

When downtown turns into the site of the bug-battle of the century (insects vs. arachnids), it's up to Ty and Abby to take down Insectiva and her hated twin sister, Arachnidia (after all, arachnids eat insects).

When alligators start showing up in people's toilets, doing your business becomes risky business. Meanwhile, inventor T.P. Skinner starts selling the Gator-Guard 5000, a gator-in-the-toilet trapping system, so Abby considers him a prime suspect...or is he?

Lance Boil has planted a nanodevice in Abby's ear, and those of many other students, causing serious vertigo, as well as complete control of their every move. Ty's refusal to clean his own ears has led to a buildup of ear wax, making him the only one immune to Boil's weapon.

Sloppy Joe opens a fast-food joint with portions so big that half the food is thrown away, creating a garbage overload in the city.

The Grossologists tangle with a former hair stylist who has a space satellite that could make everyone in the world go bald.

Sloppy Joe creates a body-odor epidemic during a heat wave.

Roger Pinkeye uses smelly cheese to create a monster out of mold.

Lance Boil drops an allergy bomb at a carnival.

A major case of acne spreads through Ringworm High.

Lab Rat invents a shrink ray...but in the process accidentally creates giant dust mites, who fall to the control of Arachnidia. Attempting to correct his mistake, he only makes things worse by accidentally shrinking Paige.

An army of giant dung beetles has stolen all the manure from nearby farmland (with Sloppy Joe along for the ride), as part of Insectiva's evil plan. Meanwhile, Abby is forced to serve as the school's Hall Monitor, and help keep it clean...but Paige is determined to make her task impossible.

An exclusive spa opens and customers are raving about its fancy bath products, but they're all bug-based and created by Insectiva, the insect queen.

A disgraced opera star is set on revenge and plans to blow everyone away with destructive burps.

A candy man comes to town with treats that cause bad breath.

A mechanical swamp monster is causing power outages all over the city.

It's time for an Archer Family daughter/son and father/mother adventure while Ty and Abby take on extreme sports together with their friends Daphne, Chris, Emma, Zack and Dana, Petunia and Harvey take on a Motocross Championship

Abby notices that holiday cheer is lacking during the Christmas season, especially with Sloppy Joe playing the local Santa.

Ty and Abby recall their early days as Grossologists.

Roger Pinkeye kidnaps Lance Boil, hoping to use him to get all the Grossology secrets.

Lance Boil and Roger Pink-Eye have teamed up, and they've got a plan. They're going to make Roger's dream come true; he's going to become a Grossologist. All it's going to take is an army of rats and an evil clone of Abby! Too bad Roger's not watching out for the Lance Boil double cross!

With Abby a prisoner, her evil clone working an inside job at the Bureau of Grossology, and Ty and Lab Rat off the team, Lance Boil looks unstoppable! Now there's only one person left who can stop him, Roger Pink-Eye!

Little pet snakes are sold all over town before they morph into deadly beasts.

Frederick Follicle returns to town, bringing a hairy epidemic with him.

Insectiva and Sloppy Joe are determined to ruin Valentine's Day.

Fartor returns with an explosive plan to send a gassy meteor on a collision course with Earth.