1. Sinister Rivalry

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).

2. Flushed Away

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?

3. Vertigo A Go-Go

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.

4. Sloppy Joe to Go

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.

5. Hairless Whispers

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

6. Stinko

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

7. Mold Monster

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

8. When Allergies Attack

Lance Boil drops an allergy bomb at a carnival.

9. Pussed Off

A major case of acne spreads through Ringworm High.

10. Ask the Dust Mites

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.

12. Spa Insectiva

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.

13. Ain't Over Till the Fat Man Sings

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

14. Candy Isn't Dandy

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

15. Swamp Gas

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

16. Squirm

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

17. Let Them Eat Fruitcake

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

18. New Recruits

Ty and Abby recall their early days as Grossologists.

19. Pinkeye & the Brain

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

20. Pinkeye's Revenge (Part I)

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!

21. Pinkeye's Revenge (Part II)

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!

22. Fangs a Lot

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

23. Hirsute Yourself

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

24. Pucker Up

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

25. The Fart Side of the Moon

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

26. Night of the Living Roadkill

Darko Crevasse returns with an army of zombie roadkill animals, and he's on a mission to ruin Halloween.