Gary Grooberson was an avid fan of the Ghostbusters early in life. He later went into the field of seismology. After Summerville started to suffer an unprecendented amount of earthquakes, he went to the town in summer of 2021 to study the phenomena. To supplement his stay in Summerville, Gary got a job at Summerville Middle School teaching a summer school science course. One morning, he stopped at the school's entrance to ask Callie if she was okay. Callie told him it was her child's first day and asked him if he could imagine who they got teaching summer school. Gary informed her he was the summer school teacher. She apologized. Gary told her it was okay and pointed out most of the children were not very bright. He greeted a boy named Colin. Colin pushed past Callie and ignored Gary. Gary summarized he could basically do whatever he wanted. Callie commented that was a score. Gary agreed and called it a dream job. She walked outside, turned her head once to take one more look, then resumed walking. Gary wheeled in an old cathode tube television into the classroom and greeted his students. He introduced himself as "Mr. Grooberson" and admitted off the bat that he did not want to be in school as much they did not. He revealed he discovered a VHS copy of "Cujo" and explained to them the movie was about a rabid Saint Bernard. He refrained from giving too much away but told them to imagine if Beethoven contracted rabies and just started mauling children. He mused they would get the idea and played the movie then went into another room connected to the classroom.
Around the point in the movie when Cujo attacked Karen's car, an earthquake went off in Summerville. Gary went to an instrument and watched it. Phoebe walked in and stared at his research on the wall. She asked what it was. Gary was surprised and informed her there was a highly entertaining movie about a killer dog happening right over in the classroom. Phoebe asked if that was a seismic map on the wall. Gary confirmed it was and asked her how she knew that. She explained she guessed it was a seismic map because it was a map of seismic activity. Before Gary could speak, she asked him if he was a seismologist. He asked her if that seemed hard to believe. Phoebe stated she figured him for a football coach. He was beside himself. Phoebe looked over some papers and noticed the patterns were not tectonic or volcanic. Gary was intrigued and drew out a volcanic and tectonic earthquake. He stated how the volcanic one builds and crests and how the tectonic has a little p-wave followed by a large s-wave. Phoebe stated she knew that and she was not an idiot. Gary agreed then drew out the pattern in Summerville: a large p-wave and a small s-wave like an explosion. Phoebe asked him where it was coming from. Gary admitted he had no idea and revealed he could not triangulate it despite setting up geophones. Phoebe asked if he used three. Gary confirmed he knew how many sides there are in a triangle. Phoebe joked she thought he was being obtuse then she winked. Gary stared at her then asked if that was a geometry joke. Phoebe confirmed it was joke and explained that was why she winked. Gary understood and found it so terrible he loved it. He continued and explained to Phoebe that Summerville was nowhere near a tectonic plate, never had any underground volcanic activity, was near no fault lines, and never had any frakking took place there and added there was not even any loud music yet the town was shaking on a daily basis. They looked at the seismic map. Phoebe speculated it could be the apocalypse. He looked at her.
The next day, Gary played "Chucky" for the class. While the other students watched Chucky attacking Karen Barclay, Podcast attempted to pry Phoebe's Trap open with a wooden ruler. Part of the ruler snapped off. Gary looked up from his comic book and quickly got out of his chair. Gary was impressed with their killer replica. He picked up the Trap and admired it. Podcast agreed. Phoebe asked him what it was a replica of. Gary was shocked at her question. He told them it was a Ghost Trap. They looked at him blankly. He looked at Podcast and wondered how of all people, he knew nothing about it. Podcast stated he was ashamed. Gary admitted he was obsessed was Ghostbusters and equated New York in the 1980s to "The Walking Dead." He looked at every inch of the Trap. Phoebe asked him if it just stopped. Gary recalled there was no ghost sighting in 30 years. A small gray mist seeped out then sucked back in the Trap. Gary dropped the Trap. The Trap cackled. He crouched down and asked them if that was a real Trap. Podcast confirmed it was. Phoebe told him it might be and revealed she found it in her living room. Podcast added she lived on the Dirt Farm. Gary asked that was the really spooky one. Podcast told him it was farm that read "DIRT" on it. Phoebe asked what happened in New York. Gary showed them a recording taken by someone during the Manhattan Crossrip of 1984 and explained the whole city was freaking out and then these physicists showed up in their portable proton accelerators and blew the roof off a Manhattan high rise.
Gary soon realized none of it was ringing a bell with them. Phoebe pointed out it was decades before she was born. Podcast believed that all happened. Gary guessed her father never mentioned it. Phoebe stated was only with her mother. Gary commented "cool" then slipped away. Podcast questioned why he said that. Gary wondered if the Trap still worked. Podcast suggested they try to open it. Gary lit up at the thought of that. After school, Gary clamped jumper cables on a school bus engine and on the Trap. He picked up a pair of safety glasses and handed one to Phoebe. She wad amused two millimeters of plastic was considered eye protection. She asked them if what they were doing was safe. Gary stated it was not safe and history was safe. He walked to the driver window of the school bus while Phoebe uncurled the Trap's line. Gary called geometry safe. He declared science was all particle accelerators and hydrogen bombs or giving yourself the plague and gambling on the cure. He handed the other pair of safety glasses to Podcast, who sat on the bus driver's seat. Phoebe placed the trap pedal down between the two school buses then she stood near the open door. She called science reckless. Gary agreed it was reckless, like punk rock, and called safety pins the nipple of academia then told Podcast to fire it up. Podcast started the ignition. The Trap cackled. Gary exhaled and admitted he always wanted to open a Trap. Phoebe took cover behind the door. He pushed the pedal down with his foot. Nothing happened. He stomped the pedal twice more. Nothing happened. He held out his hand to tell Phoebe to stay there. He approached the Trap in anticipation. He tapped the Trap doors. It suddenly opened in a flash. He fell on his back. The spectral form of Vinz Clortho roared then flew towards the Shandor Mining Company property. Phoebe turned away as it passed by, shattering the windows on Gary's car and both buses. Podcast stepped outside and raised his arms in triumph. Gary became uneasy and suggested they leave. Phoebe pointed out he was an adult. Gary noted he was and that made him liable. Gary took the clamps off the Trap then drove Phoebe and Podcast to the Farmhouse. He grimaced as he plucked a small piece of windshield glass that was still on the frame.
Podcast narrated into his boom mike after he entered the house. He took note of the presence of doors and windows like any ordinary house but also acknowledged the distinct smell of evil. Gary asked him what he was doing. Podcast likened it to setting mood by giving a little color. Gary found it creepy but he dug it. They looked around in the study. Podcast found an Aztec Death Whistle. Gary recognized it and recalled it repelled spirits. Podcast blew into it. Callie walked into the study to see what the horrific sound was. Podcast asked if he could keep the whistle. Callie told him to keep it as long as he did not use it again. Gary greeted her. She noted he brought them. Gary stated it was a service he provided, he was also an escort. She reacted. He admitted that came out wrong. She agreed. Gary admitted he always wondered what was inside the Farmhouse. Callie informed him the only thing lurking inside was her slowly dying soul. Gary asked if that was what the smell was. Callie quipped it was not dinner. Phoebe and Podcast stared at them in disbelief. Callie was about to offer something but he quickly accepted. She admitted she had no food. Callie suggested a tour. He accepted. She showed him the dining room. Podcast quickly deduced Gary was trying to bone Callie. Gary noticed an ancient looking map written in some kind of cuneiform. He realized it was a map of Summerville even though it was written in a language from thousands of years ago and the town was less than 100 years old. He was surprised at how uninterested Callie was in it and asked to have it. Callie allowed him to take it but warned him that was how it started: first a map, then you move into a haunted house, and then everyone started calling him a "Dirt Farmer." He smiled then asked if Phoebe would want to hear about the map, too. Callie believed Phoebe would find something else. They agreed to grab dinner the next day.
Callie and Gary went to Enjoy Garden Restaurant for dinner. Gary went on about how Summerville never had earthquakes but between 2010 and 2016, there was a thousand. Callie asked what happened. Gary informed her oil and gas companies pumped millions of gallons of salinated water deep into the Arbuckle Formation. He paused and asked her if she was drunk or really bored. She denied it. Gary noted he saw her falling asleep. Callie stated she was allergic to science. Gary suggested Benadryl. Callie told him she tried whiskey. Gary claimed science was amazing, pure, an absolute, and an answer to all the madness. He asked her why she disliked science then asked if Phoebe's dad was a scientist. Callie found that gross. Gary probed what the dad's deal was. Callie claimed it did not matter but told him anyway that the father got along fine with Trevor but couldn't really connect with Phoebe. Gary thought he sounded like a royal dirt bag. Callie corrected him and said he was just a very ordinary dirt bag. Gary took solace that Phoebe turned out okay. Callie hoped so and was worried because she kept her on the outside. Gary assured her Phoebe was just an awkward nerdy kid but she was awesome like her mother. Callie shared her wish that Phoebe would relax and get into some trouble. Gary believed there was plenty of time for that and joked she could take up pole dancing. Callie quipped she was not very coordinated. Gary joked that did not matter. She chuckled. Muncher later flew through the restaurant and startled Gary and Callie.
Callie and Gary ended their date and headed to the Summerville County Sheriff's Department. Callie asked Deputy Medjuck where her children were. Medjuck informed her they were in lockup. She stated her children were not criminals. Medjuck believed her in a sarcastic tone. Sheriff Domingo stepped out of his office and told Callie they were driving without a license, had an expired registration, and were speeding. Callie presumed they were not the first to go joyriding in Summerville. Gary protested and pointed out it was a Saturday night. Domingo confirmed they were not the first to joyride but they were the first to destroy half of Main Street with a Proton Pack. He had no idea what it was and pointed to it on the front desk. Gary was amazed by the sight of it. Phoebe and Trevor were escorted to the front. Callie asked them what the hell they were thinking. Gary joined in and pointed out they could have really hurt themselves. While Callie's back was to him, Gary's face indicated the opposite and he thought they did something really cool. He casually introduced himself to a confused Trevor. While Callie filled out the release form, Gary leaned toward Phoebe and asked in a whisper if she caught anything. Phoebe indicated to him a ghost was in the Trap. Callie told them they were leaving then reminded him he was supposed to look after Phoebe this summer. Gary was surprised. Callie clarified she was talking to Trevor. Trevor quibbled the incident was Phoebe's idea. She had an outburst over the equipment and Ecto-1 remaining at the sheriff's office and her grandfather being insulted. Gary was last to leave. He nodded at Domingo, pointed at the Proton Pack unable to contain himself then left.
Gary parked in front of the Farmhouse. Everyone got out. Gary was about to say something but Trevor and Phoebe walked right into the house. Gary brushed it off. Callie and Gary both half shrugged to each other. She apologized for the night going sideways. He claimed he had a blast and suggested they continue their dinner the next night. Callie asked him if he really wanted more. Gary looked at the bright side: they had kung pao shrimp and went to jail. He was unsure how they were going to top a home run like that. Callie looked down, exhaled, and looked up again. She stated her life was a dumpster fire. Gary declared he loved dumpster fires and she should see his apartment. He corrected himself on the latter. She leaned in and kissed his cheek. He stopped rambling. As she walked to the door, he joked they were moving way too fast and she had to just relax. Gary held up a while plastic bag and offered to give the children their leftover shrimp. Callie closed the door.
Gary went to the local Walmart. Vinz Clortho, in wisp form, flew into the store after him. Gary made his way to the frozen foods aisle. He opened a door of a refrigerator fully stocked with Baskin-Robbins ice cream. He took out a Jamoca. A woman screamed elsewhere in the store. Gary turned his head in reaction but continued on to the next aisle. He saw the toppings and stepped forward to the shelf. He snickered at the sight of the blue velvet flavor and walked past a shelf of Stay Puft Marshmallows. Something moved in one of the 10 ounce bags. Gary doubled back and stared at the bag. An entity tore a hole from the inside and emerged, yawning and rubbing its eyes. It was a Mini-Puft, a tiny but not identical version of the Stay Puft Marshmallow Man. It saw Gary, smiled, and stepped forward but it fell off the bag and landed on its face. It stood up and the imprint of the shelf vanished. It stepped forward. Gary was in awe. He laughed and waved to it. It marched forward but stopped at the edge of the shelf. It turned around and looked at its surroundings. Gary poked its butt. The Mini-Puft frowned, turned around, and smiled. It bit Gary's finger.
More Mini-Pufts burst out of bags. Several on a Roomba drove into Gary's left shoe. There were tons of Mini-Pufts all over the aisle. The Roomba ran one over as it drove out of the aisle. Gary was horrified and hurried past a Fourth of July themed display for grills where more Mini-Pufts were destroying each other. Gary came out an aisle then froze. Vinz Clortho was across from him with his head in a Purina Dog Chow bag scarfing away. Gary quietly backed up. The Mini-Pufts on the Roomba crashed into his shoe then drove on. Vinz lifted his head out of the bag and stared at Gary. Gary tried to talk to it but Vinz cut him off with a roar. Gary threw his Baskin-Robbins at Vinz's head and ran away, screaming. Vinz chased after him, knocking clothing racks aside, but he slid into some mannequins. He shook a mannequin arm off its head. Gary ran out into the parking lot. Just when the automatic doors closed, Vinz burst through the glass a bit too fast and stuttered. Gary made it to his car. He jumped in headfirst through where the windshield used to be, sat up in the driver's seat and fumbled with his keys. One of Vinz's paws stomped down on the hood. He snarled. The tires squealed and flattened. Vinz looked down then turned back, roared, and lunged at Gary then possessed him. The next day, Vinz used a pipe wrench to move a Proton Cannon's trajectory and destroyed one of the other cannons preventing the cross rip inside the Shandor Mining Company mine. He rested outside until Zuul, in possession of Callie, arrived. Vinz quickly got up and briskly walked to her. He complimented her eyes. Zuul spoke in dog gibberish. He thanked her, took the flower off his ear and offered it. She ate it. They embraced and dropped down to the ground.
Zuul and Vinz walked hand in hand to the Temple of Gozer in the mine. They took their places on each side of the throne then raised their arms up. Gozerian lightning from the disturbance above the mine struck Zuul and Vinz and transmogrified them into their Terror Dog forms. Gozer climbed out of the sacrificial pit soon after. After Gozer, Zuul, Vinz, the many ghost wisps, and the Psychokinetic Atmospheric Influence was trapped, the Terror Dogs were reduced to black husks. Trevor ran over to them and pulled the head off one. Gary's head was visible. Trevor asked him if he was okay. Gary noted his hands hurt from galloping. One of Lucky Domingo's hands emerged from the other husk. Trevor ran over and helped her out. Callie and Gary talked. Gary summarized that was weird. She agreed. Gary touched his head and realized he was bleeding but did not know why. Callie informed him he headbutted a park bench. Gary remembered. After some awkwardness, Gary tried to address that they had sex when they were possessed and opened the gates to hell. Callie pointed out they saved the world after. He took solace in that.
Gary Grooberson is incredibly enthusiastic about science and Ghostbusters but feels the exact opposite about teaching summer school science.
On October 17, 2019, during the October 17 episode of "Jimmy Kimmel Live!", Paul Rudd revealed he finished filming his scenes about two weeks prior.
On December 6, a first look article included a still of Gary Grooberson holding a Trap.
On January 23, 2020, one of the stills released was of Gary Grooberson inspecting a map of Summervillie with Callie in the Farmhouse.
- Gary Grooberson's whiteboard sketches were inspired by Jason Reitman's consultation with University of Calgary geoscience professor David Eaton.
- Paul Rudd also improvised lines in a school interior scene along with what was written.
- A Zaxby's cup is in Gary Grooberson's research room. Zaxby's was one of the restaurant chains participating in promotional tie-ins for Ghostbusters: Afterlife.
- Phoebe's line stating she figured Gary for a football coach is a callback to the first movie when Dana Barrett told Peter Venkman he seemed more like a game show host than scientist.
- The comic book Gary was reading at around the 31:34 mark was Marvel Comics's Ultimate Avengers #4 (November 25, 2009).
- Gary references "The Walking Dead" franchise.
- In Ghostbusters: Afterlife's first trailer, when Gary picks up the Trap, mist is green. In the movie, it is standard smoke.
- Gary refers to when the Ghostbusters blew up the roof of 550 Central Park West in the 1984 movie.
- The clips Gary shows Podcast and Phoebe are original dailies from the 1984 movie when they arrived at 550 Central Park West for the battle with Gozer, a deleted scene of Ivan Reitman's wife and two children Catherine Reitman and Jason Reitman make a cameo as tenants fleeing 550 Central Park West, and Janine Melnitz reunited with Egon as he exits the building at the end of the movie.
- Gary admits "I always wanted to do this," in reference to using a Ghost Trap. In the first movie, Peter had a similar line when he performed the 'the flowers are still standing' trick in Chapter 13: "Nice Shootin', Tex."
- Paul Rudd and Carrie Coon improvised their characters' flirtation after Gary and Callie meet in the Farmhouse.
- The ancient map that Gary notices while inside the Farmhouse first appeared off-screen as supplemental material with a tie-in merchandise release of Reebok shoes in November 2020.
- The scene where Callie and Gary eat dinner was filmed in the Enjoy Garden on Railway Street in Crossfield.
- "Foolish Try" plays during Callie and Gary's date.
- On Callie and Gary's table are a pair of orange Neko Lucky Cat Ceramic Tiki Mugs.
- Gary mentions the Arbuckle Formation during the date. It is the deepest layer of rock underlying much of oil-rich Kansas.
- Gary mentions allergy medication Benadryl during the date.
- Grooberson picks out a pint of Baskin-Robbins. In the first Ant-Man movie, Paul Rudd's character Scott Lang briefly works at one until he's fired for lying on his resume.
- Grooberson chuckles at the blue velvet flavor of ice cream topping, a nod to David Lynch's "Blue Velvet" movie.
- Grooberson was about to call Vinz a nice doggie like Louis Tully did in the first movie but is interrupted by a roar.
- Grooberson running to his car and Vinz catching up was a night shoot in the Deerfoot City Walmart parking lot.
- Like Louis Tully, Grooberson has an awkward moment before he is possessed. The weight of Vinz causes his tires to go flat.
- Gary somewhat recalls he had sex with Callie while they were possessed and she confirms it. In the first movie, there is a deleted scene "No, Louis!" where Louis somewhat recalls it but Dana Barrett flat out denies it.
- Phoebe Spengler (2022). Ghostbusters: Afterlife Chapter 8 (2021) (Blu-Ray ts. 46:40-46:43). Sony Pictures. Phoebe Spengler says: "His name is Gary Grooberson."
- Gary Grooberson (2022). Ghostbusters: Afterlife Chapter 3 (2021) (Blu-Ray ts. 18:25-18:27). Sony Pictures. Gary Grooberson says: "My name is Mr. Grooberson."
- Phoebe Spengler (2022). Ghostbusters: Afterlife Chapter 4 (2021) (Blu-Ray ts. 21:17-21:18). Sony Pictures. Phoebe Spengler says: "You're a seismologist?"
- Gary Grooberson (2022). Ghostbusters: Afterlife Chapter 5 (2021) (Blu-Ray ts. 31:55-31:58). Sony Pictures. Gary Grooberson says: "Oh, I was obsessed."
- Gary Grooberson (2022). Ghostbusters: Afterlife Chapter 4 (2021) (Blu-Ray ts. 22:07-22:10). Sony Pictures. Gary Grooberson says: "I set up geophones, but I can't triangulate."
- Variety "Paul Rudd Joins 'Ghostbusters 2020' (EXCLUSIVE)" 6/27/19
- Ghostbusters Tweet 6/27/19
- MSN/ET Online "See 'Ghostbusters' Legend Dan Aykroyd Brave a Terrifying New Maze!" 01:02-01:13, 9/13/19 Ivan Reitman says: "Well, he's a seismologist who's come to this small town because they've been having mysterious earthquakes. He's also teaching summer school there. And he's extraordinarily funny."
- Jimmy Kimmel Live! 10/17/19 on ABC, 20:40-20:42 10/17/19 Paul Rudd says: "I just finished, uh, about two weeks ago."
- Vanity Fair "First Look at Ghostbusters: Afterlife" 12/6/19
- Vanity Fair/Hollywood 2020 "Exclusive: Hanging With Bill Murray on the Set of Ghostbusters: Afterlife" 1/23/2020
- CTV News Calgary "University of Calgary geoscience professor adds movie consultant to his title" 3/2/3022 David Eaton says: "I actually was just sketching on my whiteboard and some of the sketches that I made actually found their way into scenes in the movie. Which you know really tickled me to see that happening."
- WFAA "Ghostbusters: Afterlife A chat with Logan Kim" 1:36-1:45 2/15/2022 Logan Kim says: "And he, you know, he made up like a bunch of the lines he said so he got to kind of play around with it and he's perfect with improv and I love so much he's such a funny dude."
- JTFPod YouTube "Ivan Reitman & Jason Reitman - Full Interview" 23:10-23:35 11/12/2021 Jason Reitman says: "He and Carrie have a lovely moment where it's this-this flirtation in the Farmhouse after they first meet and they and they just came up with that-those beats whole cloth right in front of me and it was absolutely wonderful and they made Gil and I look like better writers and of course there's Bill Murray."
- Reddit user Tiefighter21 "Easter Egg from New Movie Which Came..." 11/4/2020
- From The Movie " Neko Lucky Cat Ceramic Tiki Mugs" 2017
- Callie Spengler (2022). Ghostbusters: Afterlife Chapter 8 (2021) (Blu-Ray ts. 46:31-46:35). Sony Pictures. Callie Spengler says: "So tomorrow I was thinking of grabbing dinner with Gary."
- Phoebe Spengler (2022). Ghostbusters: Afterlife Chapter 8 (2021) (Blu-Ray ts. 46:43-46:46). Sony Pictures. Phoebe Spengler says: "You have a date with Gary Grooberson."