Arin: Hey I'm ghoul
Both: And we're the Ghoul Grumps!
At the end of each of the intro clips, a secret message is played backward, which is different every time.
In 2013, the messages were more menacing due to more vocal effects. From 2014 onward, the messages are only given an echo effect in addition to the creepy noises and being played backwards.
- Goosebumps HorrorLand: Danny: "Bananas are delicious."
- Cities on Flame: Danny: "God dammit, Ross!"
- Slinking in the Kitchen: Danny: "I'm into some weird butt stuff."
- EXtreme Excitement: Danny: "Get outta here!"
- Tentacle Trouble: Danny: "Mycaruba! Dun-nu-nu-nuuuu!..."
- I Believe in You: Danny & Arin: "I wish I could go back to pooping regularly!"
- New Kid: Danny: "Do you guys like football? I kinda like football..."
- This is Boss: Danny: "I take my pan-seared salmon medium well!"
- Special Delivery: Danny: "Barry says the things I'm saying here are getting too long. Do you think so? Like, comment, and subscribe!"
- Wall of Spear : Danny: "Oh hey, how's it going?"
- Finale (Maniac Mansion): Danny: "Inky was the best ghost in Pacman!"/Arin: "No he wasn't!"
- Where's the Wolf: Arin: "Aaaaand weeeee're theeee gruuuuuuuuuuuuuuuuumps!"/Danny: "Nailed it!" (laughter)
- The Addams Family: Pugsley's Scavenger Hunt: Danny: (loud mumbling sounds) "Oh, you thought I was gonna say something?"
- Finale (Castlevania: Dracula X): Danny: "This is what a fart sounds like backwards!" (farts)
- Give Me a Sign!: Arin: "One, two, three, I've gotta go pee!"
- Air Burgers: Danny: "My favorite color is potato!"
- Clear the Room!: Danny (singing): "Barry what's it like to eat lots of dicks? Maybe you could tell me? I'm asking for a friend."
- Horrible Ninjas: Arin: "No mayonaise please. I'm allergic to white people!"
- Droppin' Pearls: Danny: "Everything sounds scary when it's backwards! NNG!"
- Shaggy Time!: Arin (rapping): "He's a real cool, real cool Radical Rex! He's a real cool Radical Rex!" Danny (singing): "Radical Rex!"
- Can't Be Tamed: Danny: "Four score and seven years ago, in order to form a more perfect union, our forefathers touched my diiiiiick!"
- Werewolf: The Last Warrior: Arin: "Game Grumps fun fact: I actually /have/ peed in Dan's tea." Danny: "...what?"
- Ghost in the Sack: Arin: "My father wanted to name me Roger!"
- Life and Gun: Danny: "Looking at horns makes me purple. Seriously!"
- Bamboozled: Danny: "'Butts' said backwards is 'tubs!'"
- Aliens Exist: Danny: "The best class in Dungeons and Dragons is cleric!"
- Goofy Ghosts: Arin: " Yllem sra oui! ... It's 'You are smelly' backwards."
- Silent Hill: Play Novel: Arin: "The color purple makes me horny. No joke! No joke. Okay."
- PARTY UP IN HERE: Danny: "Are you playing this backwards?"
- Killing Time: Arin: "Call up your best friend. Tell them how much they mean to you. They'll really appreciate it." Danny: "Satan is Lord!"
- A Dangerous Pickle: Arin: "Once upon a time I stuck a carrot in my butt! And it was good!"
- Frankly Embarassing: Danny: "The state's called Wyoming? I say 'Why-not-oming!' Nyahahahahaha *fart noise*"
- Tough as Nails: Arin: "What do you mean you don't know how to repair electronic toothbrushes? Aaah!"
- Everything's Broken!: Danny: "They call me, 'El Chupacabra.' That's Spanish for, 'The Chupacabra.'" Arin: *giggles*
- Scorpion Supremacy: Arin: "Dell Inc. announces acquisition of EMC Corporation. For U.S. dollars, sixty-seven billion!"
- Mowing the Lawn: Arin: "Babies could play this game, what?" Danny: "Yes they could." Arin: "Babies?" Danny: "Okay!"
- Diggin' and Dodgin': Arin: "If you reverse this, you will be cursed for a thousand years until you send it to five friends! Send it to five friends! Or your dad will kill you!"
- Chainsaw Action: Danny: "I'm still pissed off about Ross's Mario Maker levels."
- Cutscene Quest: Danny: "I'm very close to the microphone." Arin: "Me too!" *Danny laughs*
- Zombie Hornets!!: Arin: "MmMMmm! How did the Sarlacc Pit end up pooping out (???) Boba Fett!" Danny: "How?" Arin: "With Sarlaxitives! MmMMmm!" Danny: "Oh god...Funny joke..." Arin: "FUNNYYYY JOKE!" Danny: "Jesus..."
- Legit Fear/I Spy Spooky Mansion: Arin: "Randal Stevenson, go to your room!" Danny: "But Mooom! Daaad?" Arin: "Let's do that again." Danny: "Okay." Arin: "Randal Stevenson, go to your room!" Danny: "But Mooom! D-Dad? Sorry, er, it's dark in here...*snickers*"
- Ugly Zombie Dogs: Arin: "*angrily* Tomato soup goes great with grilled cheese!"
- Log Jumping: Arin: "*laughing like a witch*"
- Don't Get Crushed: Arin: 'My dad can beat up your dad."
- RRROOOAAARRR: Arin: "Orange juice is delicious." Danny: "Says SATAN!"
- Burn Them!: Arin: "Price check on one banana."
- Actually Kinda Tough: Arin: "Ever notice how hard it is to cut up a pineapple?"
- That's a Fast Zombie: Arin: "I prefer Tootsie Pops."
- Lawnmower Man: Arin: "Brought to you by talking backwards."
- Soccer Cheaters: Danny: "Enter the taco forest and despair."
- Skuljagger: Danny: "*nonsense* I said backwardsly."
- ZomBEE: Danny: "AWOOOOO!"
- Nutmare Busters: Arin: "What do you think my life would be like if my name was Steven?" Danny: "Pretty Similar."
- The Giant Snake Episode: Arin: "Mmmm... I said to him backwards."
- What's Even Happening?!: Arin: "HAPPYHALLOWEEN!"
- That's A lot of Plot: Arin: "Spooky Scary Halloween shit." Danny: (laughter)
- Lost Base Escape (episode): Arin "Bleh I want to suck your penis"
- A Pun-filled Episode!: Arin: "Trick or treat, smell my feet, give me something...made of meat." Dan: "Oh." Arin: "Mmm." Dan: "Yeah."
- The Youthdrainers (episode): Arin: (snores) Dan: "Arin wake up it's time for Ghoul Grumps." Arin: "Huh? Oh. Is it scary?" Dan: "Yeah I mean, fucking sure."
- Odd Photographer: Dan: "(cries) I want to play Game Grumps." Arin: "Okay let's do it." Dan: "Oh."
- Tungulus: Dan: "What color is puce?" Arin: "seventeen." Dan: "Oh." Arin: "Yeah."
- Hungry Boy: Arin: "I'm gonna shit my pants real quick." Dan: "Well."
- 24 Hours: Dan: "I bet the hamburger helper gives great hand jobs." (he and Arin then laugh)
- Professional Sneaker: Dan: "I will give you five dollars...if you shove an entire hand up your butt...but it has to not be your hand."
- Click For Love: Dan: "Satan is lord." Arin: "ha ha, I agree." Dan: "Just keeping it old school." Arin: "Right on."
- Creepy Nurse: Arin: "Hashtag not blessed." Dan: (snickers)
- Fingerblasting: Arin: "Hashtag not blessed." Dan: (snickers)
- Tough Zombies: Dan: "Wow, Happy Halloween everybody." Arin: "Happy Halloween." Dan: "Happy Halloween." Arin: "Happy Halloween." Dan: "Happy Halloween." Arin: "Happy Halloween." Dan: "Happy..."
- Dark Night: Dan: "Arin would you consider my thighs thick, like T-H-I-C-C thick?" Arin: "No."
- Friday the 13th: The Game: Arin: "Better make you some pork stew."
Nightmare Before Xmas Edit
- Granny: Arin: "Mmm... Delicious!" Dan: (laughter)
- Chicken in the Darkness: Around the Corner - PART 1: Dan: "This is a backwards message!" (laughter) Arin: (wheezes)
- Krampus: Krampy - PART 1: Arin: "It's Halloween!" Dan: "WHAT?" Arin: (screams)
- Chicken in the Darkness: Jump Scare Make Boys Cry - PART 2: Dan: "Thank you, yeah, we love you!" Arin: "Happy late Halloween, happy... Christmas!"
- Krampus: Krampier - PART 2: Dan: "Kill your parents! Won't you?" Arin: "Duh-dun-dow!"
- Skifree: Arin: "Ope-ope-ope-ope oppa Game Grumps style!" Dan: "Huh-ho, fuckin' timely, dude!"
- Krampus: Krampiest - PART 3: Arin: "Support Satan by killing your parents!" (evil laughter) Dan: "Oh my god..."
- Santa's Revenge: Arin (far away, with a Southern accent): "I came from Kansas!" Dan: "Get the fuck out of here."
- Kuchisake Onna: (silence)
- Yomawari: Poor Poro - PART 1: Dan: "I'm just gonna come out and say it: Sonic rules, and fuck you if you think differently." Arin: "Bold statement."
- Trivia Murder Party: Life-Ending Trivia - PART 1: Dan: "Heyyyy!" Arin: (inaudible words)
- Yomawari: Run 'n Hide - PART 2: Dan (singing in a nasally voice): "There is something stuck in my teeth!"
- Trivia Murder Party: A Close Finish! - PART 2: Arin: (smooch sound) "Gimme a kiss!" (smooch)
- Yomawari: Draining the Cool Pool - PART 3: Dan (singing in Hebrew): "Barukh ata Adonai Eloheinu, melekh ha'olam, asher kid'shanu b'mitzvotav v'tzivanu l'hadlik ner shel Hanukkah."
- Translates to: "Blessed are You, Lord our God, King of the universe, Who has sanctified us with His commandments and commanded us to kindle the Hanukkah light[s]."
2019 broke from the tradition of having backwards messages in every video, and instead, each video used the one from Krampus: Krampier: Dan: "Kill your parents! Won't you?" Arin: "Duh-dun-dow!"
- Goosebumps HorrorLand
- Castlevania: Dracula X
- Maniac Mansion
- The Addams Family: Pugsley's Scavenger Hunt
- Luigi's Mansion
- Scooby-Doo and the Cyber Chase
- Werewolf: The Last Warrior
- Alien 3
- Silent Hill: Play Novel
- Resident Evil HD Remaster
- The Twisted Tales of Spike McFang
- The Lawnmower Man
- Sküljagger: Revolt of the Westicans
- Nightmare Busters
Main Article: A Message About Ghoul Grumps
In 2018, with the 10 Minute Power Hour and Game Grumps Live Streams taking up much of their schedule, Ghoul Grumps had been relegated to a single episode, angering some fans enough to send negative feedback onto other videos. On November 6th, 2018, Arin posted a video on the channel apologizing for forgetting the series, and promised to make up for it with a horror-themed Jingle Grumps this year.
Ghoul Grumps: Nightmare Before XmasEdit
On December 11th, 2018, Game Grumps debuted Ghoul Grumps: Nightmare Before Xmas as a way for Arin to make up for forgetting about Ghoul Grumps in October until the last minute. It debuted with the horror game Granny.
On September 12th, 2019, Arin confirmed in Is Ghoul Grumps happening!? on The Grumps channel that the 2019 Ghoul Grumps will happen in October as normal meaning that Ghoul Grumps: Nightmare Before Xmas was a one-off event.
- Chicken in the Darkness
- Viscera Cleanup Detail: Santa’s Revenge
- Kuchisake Onna
- Yomawari: The Long Night Collection
- Trivia Murder Party
- The Grump Heads for the Ghoul Grumps: Nightmare Before Xmas run are based on the two faces of the Mayor of Halloween Town, from the Disney film Nightmare Before Christmas. The logo was designed by Brady Hartel, along with some assistance from Jonathan Kim, both of whom are artists at Lab Zero Games. Art for the branding was also provided by regular contributors TopSpinTheFuzzy and Krooked_Glasses. 
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