At some point in time, a nest of vampiric entities settled in Coney Island on the southern tip of Brooklyn. Dressed as clowns, they set out to feed on laughter. If unable to, they invoke it with their disguises. At their choosing, they can also turn human victims into one of them. An eyewitness saw one of the clowns feed on a man who missed a local bus and called the Ghostbusters for help. They tracked the clown to another victims' apartment room and fought it. At the time, Eduardo Rivera and Garrett Miller were competing with each other. Eduardo managed to confine and trap it himself. The Ghostbusters were unaware that the other three clowns were watching from afar. They decided to get revenge on Eduardo and targeted him as a replacement for their fallen comrade. While Eduardo was heading home, he was attacked by their jack-in-the-box emanation and cut.
The Ghostbusters then received a call to Laugh Riot at 23rd and Sheldon. The trio of clowns easily escaped capture but Eduardo's transformation began to progress. Egon Spengler discovered Eduardo's white blood cells were mutating. Upon analyzing one of the clowns' gloves, trace amounts of beach sand, popcorn, and mustard were discovered. As the remaining Ghostbusters went to investigate Coney Island, Slimer mistakenly released Eduardo. Unable to invoke laughter from Egon, Eduardo traveled to Coney as a fully transformed clown entity. He feed on Roland Jackson and stalked Kylie Griffin and Garrett. They then trapped the other three clowns. Hopelessly overpowered by the head entity, Kylie and Garrett were saved when a laughing man in a trench-coat arrived out of nowhere. It was actually Slimer with a tape recorder. Kylie, Garrett, and Egon, armed with a Field Projector, trapped the entity. Eduardo was returned to normal and all victims were redistributed around the fair grounds, albeit naked. They all also had short term memory loss and had no recollection of their ordeal. The Extreme Ghostbusters go after vampiric clowns that devour victims that laugh in their presence. Also they must find a cure for Eduardo, who has been turned into a clown by the vampiric entities as revenge for capturing one of their own. A man missed an evening bus. He walked down an alley and hummed to himself. Above him, on a roof, a clown watched. The man noticed someone was following him and he ran for it. The clown plodded along after him. The man reached a dead end and turned to confront his stalker. He was relieved when his would-be stalker was just a clown. The man let an insult slip out and the clown glared at him. The man apologized and opened his wallet. The clown started juggling. The man played along and laughed. The clown stopped and slapped the wallet away. He grabbed the man and a monstrous "tongue" emerged from his mouth. It sucked up the man whole. As the man's clothes dropped to the ground, the clown walked away and belched.
At the Firehouse, Roland was laughing at his own joke. He was the only one laughing. Garrett and Kylie were silent. Slimer and Eduardo were asleep on the couch. Roland reiterated his Dwain the bathtub joke but soon realized no one else thought it was funny. Garrett looked over at Slimer and Eduardo. He picked up an empty bag of potato chips, blew it up, then smacked it. Slimer flew off into the ceiling. Eduardo sat up but Slimer landed right on top of his head. Kylie joked Eduardo needed as much beauty sleep as he could get. Garrett confronted Eduardo for slacking off. Eduardo didn't take too kindly to Garrett's presumptions. Egon came out of the kitchen and informed the team there was a call. Ecto-1 pulled up to the alley where the man was eaten by the clown. Kylie picked up a reading on the P.K.E. Meter. Roland gathered the man's clothing into a sack. The eyewitness, a woman in hair curlers and face cream, sneaked up on Eduardo and startled him.
The woman witnessed the man melting and decided to call the Extreme Ghostbusters instead of the police. Kylie pressed her more information. The woman recalled the victim was laughing before he melted. She couldn't make out the perpetrator but saw he wore big shoes. Eduardo joked around and things became heated between him and Garrett. The team split up and searched the general area. Eduardo turned a corner and ran into Garrett. The clown stalked Kylie. Kylie knew she was being followed and radioed the others. She dropped the radio and picked it up. But the clown grabbed her. It brought out a sock puppet and tried to make Kylie laugh. Kylie was silent and unmoved by it. The clown threw her down in frustration and ran away. Roland, Garrett, and Eduardo caught up to Kylie. Garrett and Eduardo were underwhelmed when Kylie revealed they were chasing a clown. The clown heard laughter from an apartment unit and easily scaled the wall to the window. It observed a man laughing at a stand up comedy show. It slipped inside and ate the man. The Extreme Ghostbusters heard the scream and ran to the apartment. Garrett opened the front door but Eduardo forced his way in first. Kylie realized the common link was laughter. Roland laughed at the show and the clown emerged from the armchair. It grabbed Roland but Eduardo and Garrett blasted it off him. Kylie threw out a Trap but the two fought over the clown. Eduardo kicked Garrett away and trapped the clown himself.
Eduardo danced in celebration. Kylie asserted it was too early to celebrate. There could be more clowns. Eduardo twirled the Trap on a finger and welcomed the challenge. Just outside on a roof across from them, were three more clowns. On the way back to headquarters, Kylie presented her theory the entities were attracted to laughter. It's the only thing that tied the victims altogether. Roland asked the obvious question, why they were dressed up like clowns. Kylie believed their appearance was bait, a way to invoke laughter if it couldn't be found. The clowns followed after Ecto-1. The team dropped off Eduardo at his house. Eduardo was bummed. He still wanted to blast more clowns. Kylie informed him they were going to take the clothing back to Egon to analyze. Roland promised to pick him up the next day. Eduardo noticed a jack in the box on his mail slot. Eduardo played it and a clown popped out and bit him on the arm. Eduardo swatted it aside. The toy transformed into a more gruesome form and chased after Eduardo. Eduardo ran for it and caught up to Ecto-1 on foot.
Eduardo jumped onto Roland's lap and put Ecto into reverse. He backed up right over the toy and squashed it. Garrett mocked Eduardo but Kylie noticed a bad cut on his arm. Eduardo chalked it to nothing but laughed oddly. The clowns emerged from a manhole and entered the Laugh Riot. The laughter inside soon turned into screams. Egon hailed the team on the radio and informed them of a call from 23rd and Sheldon. Soon after, the team arrived at the comedy club amid a feeding frenzy. One clown used a horn to literally blow the team away. Another tried to throw pies at them. Only Garrett was nailed. A couple walked in - the man promised a real laugh and chuckled. One of the clowns grabbed him but Garrett punched him. He struggled to rip the clown's glove off the man's neck. They saw the victim's faces on the clown's exposed hand. The clown ran for the exit but Eduardo was waiting outside. However, Eduardo let the clown go. He informed Roland the clown got away. Garrett was not pleased at the news. Eduardo grabbed a seltzer bottle and sprayed the rest of the pie off Garrett's face.
Kylie presented the others with a new theory, the entities were vampires who feed on laughter instead of blood. Roland got a residual reading from a loosened manhole cover. Eduardo suddenly started juggling, then somersaulted off a wall, and caught the three balls. Kylie noticed his shoe prints had grown to a size 40! Kylie looked at Eduardo's cut, it got worse. Eduardo worried something was wrong but then started laughing manically. They took Eduardo back to the Firehouse and placed him in an isolation chamber in Egon's lab. Egon confirmed Eduardo's white blood cells were mutating and he was slowly transforming. The others wondered why the clowns didn't eat Eduardo. Egon began to believe in Kylie's vampire analogy and surmised that also like Vampires, the clowns had the option to also turn their victims, like Eduardo, into one of them. In this case, it was retribution for their captured comrade. Egon guessed the only way to cure Eduardo was to trap all of the clowns. But they didn't know where the clowns were located. Egon turned to the glove recovered from Laugh Riot and examined it under a lens. He noted traces of beach sand, mustard, and flecks of popcorn. To Garrett, it sounded like the clowns were holed up on Coney Island. Kylie agreed and the team headed out. Egon elected to stay behind and continue to study Eduardo's blood factors in hopes of discovered the basis of an antidote. Slimer flew into the lab and was tricked into freeing Eduardo for some cotton candy. Egon and Slimer looked on in horror as Eduardo emerged from the chamber already partially transformed into one of the clowns.
At Coney Island, the team approached a Fun House section. Garrett was worried Roland's sense of humor might be a liability. Roland assured Garrett he wouldn't be laughing anymore. However, Roland was reminded of his bathtub joke and laughed aloud. The laugh echoed. He was soon devoured, by clown. The clown was Eduardo! Kylie and Garrett tried to stop him but, they risked hurting him and Roland. So as they pursued him, they ran into the other clowns. Garrett punched one in the face. It's face crumbed and revealed its true form was the monstrous "tongue," - a worm-like entity. Kylie and Garrett trapped it and got more Traps from Ecto-1. The other two clowns attacked them but Kylie trapped them all at once. A trap door opened up beneath them and they fell down chute into in a pool of water. They realized Eduardo pulled a lever and he was still a clown. As they readied themselves to shooting Eduardo to save Roland, the head vampire, a bigger more monstrous slug, revealed itself from the giant ticket stand.
The head vampire grabbed Kylie and Garrett and tried tickling them into laughing. Just as Kylie laughed, the vampire's attention turned to a figure in a trench coat laughing. Kylie and Garrett were released It was Slimer, with a radio playing a recording of laughter. The vampire threw the radio down in confusion. Egon then stepped forward, armed with his Field Projector. Garrett, Kylie, and Egon blasted the head vampire. Eduardo floated up into the air and reverted to normal. Slimer threw down a Trap but was nearly sucked in himself. Once the last vampire was trapped, Eduardo fell to the ground. Slimer hugged Eduardo, happy to see him back to normal. Eduardo had no memory of being a vampire clown. Roland was back but totally naked. After Slimer had a laugh, he handed Roland some clothes. Kylie realized Egon wasn't a laugher either, thus he was spared by Eduardo. They set out to find the other victims. Eduardo suddenly remembered the clowns and sprang into action. Garrett assured him it was all over.
The first one resembled the usual appearance of a clown. The other three resembled a chicken, a clown resembling a knock-over toy dressed in black, and a massive, scary clown wearing boxing gloves and a tutu. The fifth one was their master, a giant lamprey creature hiding in a ticket booth shaped like a clown.
- The weakness of the vampires is that they can't prey on someone unless they laugh first. To counter this, they use their clown disguises to try to bait them into laughing.
- In addition, the giant leader of the clowns has several tentacles with tips covered in soft, feather-like appendages it uses to tickle victims into laughing.
- What's worse is that they have the ability to infect other people using a special jack-in-the-box to turn them into vampire clowns too.
- A ghostly clown appeared as a boss in Extreme Ghostbusters: Code Ecto-1, but he lacks any resemblance to the lamprey-vampires.
- Kylie's analogy for the clowns are "Laughter Vampires". The entities' true names are not revealed. On the official website, they were simply referred to as "Evil Clowns".
- Guest star Susan Blu is also the dialogue director of the series.
- There are two versions of this episode. When this episode was shown for the first time, there was a brief one-frame animation goof—the "clapboard" was visible for one quick frame during the scene where the Extreme Ghostbusters are in Ecto-1 discussing the vampire analogy. However, in subsequent airings, the clapboard was removed and the error fixed.
- When Kylie takes a reading of the first victim's clothing, she does a play on "Something Wicked This Way Comes," a line from "Macbeth" and title of a Ray Bradbury novel.
- Eduardo retorts Bigfoot is the culprit. The original Ghostbusters encountered a Bigfoot in "Camping it Up"
- When Kylie informs Eduardo that there may be more clowns after the first one is trapped, Eduardo responds with "Send in those clowns", a reference to the song Send In The Clowns.
- Kylie claims she's not a laugher but it is later revealed she is ticklish.
- During the Laugh Riot bust, Eduardo calls a clown "Krusty." He's presumably referencing Krusty the Clown, a character from the TV show The Simpsons.
- Eduardo's shoe size is 9.
- When Egon reveals his findings, behind him is a calendar set at May. Comparing positioning of the days of the week, this May coincides with May 1997.
- Garrett refers to one of the clowns as Emmett Kelly," an American performer famous for creating the memorable clown figure "Weary Willie"
- At the end of the episode, Egon wears a special proton pack with floodlights and a modified blaster. According to Production Supervisor Shannon Muir, it is called the "Field Projector." Early in the script process, there was consideration that new equipment would be adopted and replace Proton Packs. It is also part of the deluxe equipment the Egon Spengler toy is marketed with.