After a job, the Ghostbusters return to find Ecto-1 stripped by a delinquent, and then they get an even more personal encounter with a kid gone bad. After a rally at a school, a boy named Lee approaches them, concerned about his brother Alec's spooky new friend. After some research, the team finds out the bad news — the creature is a Grundel, an evil being that corrupts and transforms children, and time is running out.
This episode includes examples of the following tropes:
- Always Wanted to Say That: When they need to find Lee's number quickly, Ray tells Slimer to "go through the phone book". The ghost does, literally, and comes out with the number written on his stomach. Peter teases Ray about having been waiting to say that, saying he's had that look on his face all week.
- Bad People Abuse Animals: Under the Grundel's corrupting influence, Alec kicks a neighbor's cat.
- Continuity Nod: According to Alec's father, the title character from "The Thing in Mrs. Faversham's Attic" is their neighbor and owns the cat that the kid kicked.
- Do Wrong, Right: Egon notes that whoever stripped Ecto-1 was very efficient; it took them under five minutes.
- Hypocritical Humor: Egon lectures Ray about the unnecessariness of "love" for a job well done, but when Janine initially leaves him out of her declaration of love to the others, he's clearly unhappy.
- If I Can't Have You…: Namedropped; Alec rejects the Grundel and runs to grab his brother, Lee, before he can fall. The Grundel tries to stop Peter from getting to the boys, saying that no one can have them if he can't.
- "I Know You're in There Somewhere" Fight: The nearly-transformed Alec's assertions that "Alec doesn't live here anymore" don't convince Peter, who insists on reminding him of his past with his brother while telling him the Grundel isn't his friend. It works; Alec breaks the connection and runs to Lee.
- Must Be Invited: The Grundel latches onto his victims by appearing before them and promising they'd have fun together if they were to let him in. It seems to have hypnotic abilities to help.
- Otherworldly Visits Youngest First: Zig-Zagged. This is The Grundel's modus operandi. It seeks out children and encourages them to do bad things, which causes them to transform into Grundels themselves. Usually, by the time anyone else in the family has any suspicion of anything going wrong, it's too late, and the child is forever transformed into a Grundel. The Ghostbusters learn that Alec is being corrupted by a Grundel from Lee.
- Papa Wolf: It's Peter's turn to play the "protective father" role. When he hears about the Grundel, he says that no one is messing with a kid in his neighborhood. He keeps trying to talk Alec out of his toxic relationship with the creature even as Alec fires blasts at him. After successfully separating Alec from the Grundel, he fights the creature to get to Alec and his brother before they fall to their deaths.
- Properly Paranoid:
- When the Grundel is nearby, the PKE Meter briefly flashes a couple of times. Egon notices this and finds each occurrence rather troubling.
- Lee talks to the guys about his certainty that something dressed in black is making Alec do bad things. Egon in particular can't shake the feeling that he's already read about such a creature, but he can't quite place it until doing more research.
- Reasonable Authority Figure: Finishing a job, the guys find Ecto-1 stripped bare. A cop, however, caught the perpetrator and tells them where their goods are being stored.
- Screw This, I'm Outta Here: Alec tampering with the proton packs causes a simple demonstration to trash much of the auditorium. When told the principal isn't around to yell at them over this, Peter says now would be a really good time for the Ghostbusters to leave.
- Shout-Out: When the other three Ghostbusters walk away, they're whistling the Inspector Gadget theme.
- Snub by Omission: Ray jokes that their lack of calls means nobody loves them and is lectured by Egon about associating self-worth with being loved. Janine reassures Ray that she loves him, Winston and Peter, but ignores Egon, much to Egon's annoyance. The three named Ghostbusters make a quick exit, followed by a dejected Egon. Janine stops him half-way up the stairs to tell him she loves him most of all; while he tries to dismiss the sentiment, he practically floats upstairs with pleasure.Janine: It's okay, Ray — I love you. I love you, too, Winston. I even love Dr. Venkman here... sort of. (Three Ghostbusters leave, whistling; Egon follows, dejected.) Oh, Egon? I love you most of all.
Egon: (smiles, then catches himself) A-hem. Yes, well... such displays of emotion are only needed by the insecure. Thanks for the thought though... - Synchronization: Even when the Ghostbusters arrive to bust the Grundel, they can't shoot it; it's connected to Alec and using their proton packs would hurt him. Luckily, Ray comes up with a solution: they need to convince Alec to break the connection. This works, and the Grundel is trapped afterwards.
- Talking the Monster to Death: While the Grundel itself is too evil for that, Peter manages to bring Alec back and get him to reject the thing by talking to him. He reminds him of his relationship with Lee, tells him the Grundel is using him, and asks if he really wants to be like it.
- That Man Is Dead: A young boy named Alec comes under the influence of a Grundel. When pleaded to by his brother, he tells him "Alec doesn't live here anymore!" He tries the same thing with Peter, who doesn't buy it.
- Too Desperate to Be Picky: After unplugging Egon's machine to keep it from making noise, Peter returns to the bedroom to find Slimer asleep on his bed. He declares that he's not that tired and walks away...before admitting that, yes, he is, and returning to stretch out next to the ghost, regardless of the slime.
- Trauma Button Ending: The Grundel lures Alec into its clutches by offering him the opportunity to do anything he wants, free of parental control. After being freed, Alec asks the Ghostbusters if he can work the siren while they're driving home. Ray says that as far as they're concerned, he can do anything he wants. Shaking his head, Alec chuckles and says he's heard that before (though he's quite happy to play with Ecto-1).
- Unwitting Instigator of Doom: While berating Alec for his recent misbehavior, Mr. Meredith again asks why he can't be more like Lee. The Grundel gets the climax going by asking Alec, "Question is, why can't your brother be more like you?" The Grundel may very well have gone after Lee anyway, but this gave him an excuse to involve Alec.
- Villainous Breakdown: After being rejected, the Grundel tries to get both Alec and Lee killed by keeping Peter from coming to their rescue. He attacks Peter, and as he's being sucked into the trap, he yells a Big "NO!".
- Why Couldn't You Be Different?: Even before the Grundel turned up, Alec was getting this from Mr. Meredith and told to be more like Lee.
