Production Credits
The episode was recorded on May 30 and 31, 1990. Frank Welker and Dave Coulier each recorded alone on May 31, 1990.
Plot
The Ghostbusters' answering machine picks up a call at the empty firehouse: a recording by Ray announces the team is on vacation until June 5. A Realtor Ghost takes advantage of the vacancy and shows a ghost family around the building. The family, the Grungies, agree to move in. The parents, Foul and Pig, begin clearing out what they consider junk, including the Proton Packs, Ghost Traps, and other equipment. They mistake the Proton Packs for leaf blowers; Foul keeps one to clean up after their pet, Yuck. The children, Bug and Smelly, claim the upstairs rooms, and the deal is done.
The team returns in Ecto-1 to find the garage door unresponsive, the sign gone, and the locks changed. They send Slimer in to investigate; he flies back out in a panic. The Grungies have completely redecorated the ground floor. The two sides argue over ownership until Foul sics Yuck on the Ghostbusters, and they are thrown out. The team tracks down two of their Proton Packs and three Ghost Traps at the city dump.
Back inside, Pig heads to the basement and mistakes the Containment Unit for a washing machine. She opens the trap grid to investigate and inadvertently releases a swarm of ghosts. Egon detects the ectoplasmic surge from outside and warns the team the P.K.E. leakage has turned the unit into a time bomb, with about an hour before it destroys most of New York City. The team changes into civilian disguises at Larry's Uniform Shop (Ray and Egon as utility workers, Winston as a fireman, Peter as a safari guide) and sends Slimer in as a scout. Slimer distracts Yuck with a mirror, scaring the ghost dog off with its own reflection, then relays the bad news from the basement.
Egon and Ray bluff their way inside by posing as gas company workers and warning Smelly the building is going to explode. She lets them in and they lock themselves in the basement to work on the manual and backup systems. Meanwhile, Smelly and Bug blast music in Egon's lab, which only accelerates the plasma dynamic buildup. Foul and Pig eventually tie up Egon and Ray, not believing the danger, and zero gravity sets in as the unit destabilizes.
Peter and Winston slog through the sewers with Slimer to reach the basement. Alligator ghosts block their path; Winston superheats the water with a Proton blast to drive them off. With minutes to spare, they break through the ceiling into the basement. Smelly finally recognizes the danger and pulls Bug away from the music equipment, but he is caught in a power surge. Slimer tackles Foul; Egon carefully unplugs the source and Bug returns to normal. Downstairs, Ray and Winston complete the reset sequence just in time.
With the crisis over, Foul concedes the firehouse to the Ghostbusters, citing the lack of peace and quiet. Pig makes him apologize, and forces Bug to thank the team for saving his life. The Grungy family departs in their Boo-Haul rental. Peter immediately suggests another vacation; one look at the wreck of the firehouse is enough for everyone to agree.
Characters
Main Cast

Peter Venkman

Egon Spengler

Ray Stantz

Winston Zeddemore

Slimer
Note: Janine Melnitz does not appear in this episode.
The Grungy Family
The Grungy family are this episode's central ghosts: a grotesque domestic unit whose appearance is a parody of the Simpsons, while their names mirror the Bundy family from Married...with Children. Foul (voiced by Frank Renzulli) is the reluctant patriarch, paralleling Al Bundy. Pig (Angel Harper) is the enthusiastic mother, paralleling Peg. Bug (Benny Grant) is the teenage son, paralleling Bud, and Smelly (Janna Levenstein) is the daughter, paralleling Kelly. Their dog, Yuck, parallels the Bundys' dog Buck. The family's moving truck bears the name "Boo-Haul," a parody of the U-Haul moving and storage company.
Containment Unit Escapees
When Pig inadvertently opens the Containment Unit's trap grid, a large number of previously captured ghosts pour out. Several are recognizable from earlier Season 6 episodes: the Mean Green Teen Machine (from "Mean Green Teen Machine"), an alien Class 7 (from "Spacebusters"), and Count Von Blukenporken's bat minions Destricon and Lucifus (from "My Left Fang"). Gorgar also appears among the escapees, despite having returned to his own world in "You Can't Teach an Old Demon New Tricks." Animax, a ghostly bounty hunter from the Season 4 episode "Short Stuff," can also be spotted briefly when Foul attacks the escaped ghosts with the Proton Pack, though Animax is oddly recolored green in these shots.