Just as Lazlo starts potty-training the babies, a diabolical diaper manufacturer brings every toilet in town to life and forces the world into wearing diapers.
After battling so many monsters and aliens, the babies take a stressed-out Lazlo to the beach to relax. The trio drives everyone else visiting mad with their antics, but Lazlo's paranoia and concern for their safety drives her to the brink of insanity!
One rainy day, the babies decide to do some finger painting. Unfortunately, their “paint” turns out to be a toxic substance that ends up bringing their drawings to life and going on a rampage through the city.
An alien race of dill pickles comes to Earth to turn the population into pickles as revenge for eating their species. Meanwhile, they seek to eliminate their biggest threat, Buck.
Hankering for a midnight snack, Lazlo and the babies visit an abandoned grocery store, where they end up fighting a mad scientist and his mutated food beasts.
When Meg's massive farts cause a hole in the ozone layer, a family of aliens accidentally drops to Earth! Now the babies and Lazlo have to keep them company while finding a way to get them back home.
A space gypsy is sent to Earth tasked to capture the babies to use them as an attraction to a galaxy zoo. To do this, he creates a voodoo doll of Lazlo and lets the babies inadvertently do the rest.
A trip to the snowy mountains takes a chilling turn when the babies meet a crew of snowboarding punks who are actually aliens planning to freeze the Earth and rocket it away from the sun.