Bats in the Belfry is the 10th episode from Season 1 that aired on November 27, 1997.
A gang of nefarious and notorious bats, including Johnny and Cookie, take over the Aliens' house. Candy thinks they are disgusting and the aliens attempt to take them out, but always fail every time.
At the end, after a bat being put Candy's underwear in his head, he finally snaps, forcing the bats to leave the Aliens' house and pack their underwear. But, he then also acts bossy and annoying to the Aliens.
If you want to see this transcript of this episode, click on to this link.