In the second episode, Spongebob thinks Gary is lonely, so he buys another pet. However, this pet tries to destroy Gary.

Chocolate with Nuts: SpongeBob and Patrick want to make some extra cash so they decide to sell chocolate bars door to door. They have no luck at first. In fact, they end up buying more stuff than selling stuff. That is, until they start lying to sell the chocolate. They claim it saves lives etc.. […]

Plankton creates a sauce that lowers the intelligence of whoever eats it. The fumes are sucked into an air vent, absorbed by a cloud, and rain on Bikini Bottom, turning everyone as stupid as Patrick. Sandy and Karen are the only ones not affected, and must re-educate the town.