Fiddleford Hadron "Old Man" McGucket is an old, deranged hillbilly who lived at the Gravity Falls Junkyard and now lives at Northwest Mansion (later renamed "Mcgucket's Hootenanny Hut!!"). He is also an occasional ally of Dipper and Mabel Pines. Once a brilliant inventor who worked alongside Stanford Pines and founded the Blind Eye Society, excessive memory wipes have left him in his current state of hopeless psychosis, although he has become more sane and normal following the events of "Society of the Blind Eye". He represents the glasses on the Zodiac.
In the mid-1970s, Fiddleford attended Backupsmore University, where he befriended Ford Pines, who perceived Fiddleford to be a "young but brilliant mechanic." Following his graduation, Fiddleford took up residency in Palo Alto, California, where he established "Fiddleford Computermajigs," a self-employed personal computers business. In the midst of his work, he received contact from Ford, who sought his mechanical genius in constructing a transuniversal poly-dimensional metavortex beneath his home in Gravity Falls, Oregon. Albeit with hesitation as to whether the device would be feasible to construct, Fiddleford agreed, leaving his wife Emma-May and their young son Tate behind to set out for the sleepy hamlet.
From then on, Fiddleford acted as Ford's research assistant, aiding him in his studies and in building contraptions such as the Universe Portal and some machinery in the underground bunker. Though Ford was annoyed by his tobacco chewing, banjo playing and hamboning, he considered him an invaluable partner.
One day, while returning from an expedition to the crashed Flying saucer, Ford and Fiddleford stopped to observe a sleeping Gremloblin. After Ford drew a picture of it, it unexpectedly woke up and attacked Fiddleford, staring him in the eyes and forcing him to see his worst nightmare. Though Ford was able to rescue Fiddleford, the encounter left the latter deeply scarred. Determined to return his sanity and eradicate the experience from his mind, he utilized his genius ability to invent a memory erasing gun, permanently relieving him of his nightmares. He continued to use the memory gun throughout his remaining time with Ford, and it is implied that he even used the gun on Ford himself after he complained of Fiddleford's reliance on it.
Throughout the construction of Ford's greatest scientific achievement, Fiddleford was given access to his laboratory hidden beneath the forest, where he utilized one of his functioning prototype laptops to aid in the ongoing research and development of the portal. The night before testing the machine, Fiddleford expressed his concerns to Ford about the portal's stability, suggesting that Ford publishes his research as a thesis and forget the portal, to which Ford- already manipulated by Bill into mistrusting Fiddleford's motives and intentions- angrily refused. The following day, on January 18, 1982, Ford and Fiddleford performed their first trial with the active machine, which quickly went awry as the dummy placed into the portal dragged Fiddleford along with it. Though his experience within the device was brief (as Ford had rescued him shortly thereafter), Fiddleford returned horrified with the visions he had endured while inside (specifically, Bill Cipher removing his exoskeleton to feed), predicting that an apocalyptic catastrophe would occur should the portal reach its full potential. This was due in part to getting a glimpse of the Nightmare Realm.
After quitting the project when Ford refused to give up the pinnacle of his life's work, Fiddleford found himself haunted by his encounters with the supernatural as paranoia and insomnia consumed him. He continued to use the memory gun. The device became an inspiration for Fiddleford to found an organization within Gravity Falls known as the Blind Eye Society, hoping to give others a similar chance at alleviating their deepest regrets and awful memories. Unfortunately, continuous encounters with paranormal entities within the town and a heavy over-reliance on his creation deteriorated Fiddleford's mind, draining him of his sanity and increasingly devolving him into a crazed and lunatic old man. By July of 1983, Fiddleford was a ghost of his former self, estranged from his wife and son and now known as the garbage-dwelling Old Man McGucket, Gravity Falls' local kook.
Old Man McGucket is first seen in "The Legend of the Gobblewonker," where he is running up to everyone and telling them that he saw the Gobblewonker and that it destroyed his boat. However, he is made fun of by the crowd and the police. Later, it is revealed that he built a mechanical version of the Gobblewonker to gain attention because his son, who is embarrassed by him, never wants to spend time with him anymore. He tells the twins that he also made a homicidal Pterodactyl robot when his wife left him, and an 80-ton 'shame bot' when his friend Ernie didn't come to his retirement party. He then went back inside his robot to continue work on a death ray.
McGucket appears next in "Headhunters." He was present at the re-opening of the Wax Museum of Mystery, and he asks if the wax statues are alive and if he can survive the wax man uprising, to which Mabel answers yes. Dipper and Mabel later find him at the junkyard. They wave at him to see if he uses his right or left hand most frequently, and he responds to them by waving his right hand, which has a young alligator biting down on it.
In "Little Dipper," he is seen at Gleeful's Auto Sale, wanting to buy a damaged used car. McGucket later wins ten million dollars by being the runner-up winner in a contest (the first place winner was Stan, who turned down the offer). He then eats the check.
In "Bottomless Pit!," he appears in Dipper's story, Voice Over, as he gives Dipper a voice-altering formula when he is embarrassed by his voice cracking. After Dipper comes back, unsatisfied with the voice induced by the formula, McGucket gives him another, though Dipper does not drink this one.
In "Carpet Diem," he is seen chasing Soos (in Waddles' body) in order to eat him. He ends up changing bodies with Candy Chiu and other characters when he follows Soos into the room with the Electron Carpet at the Mystery Shack. After everyone changed back to their normal bodies, McGucket threatened to eat Soos.
In "Boyz Crazy," McGucket appears at the Gravity Falls Civic Center and Buffet when Mabel, Candy, and Grenda practice their "obsessed boy band scream." McGucket is apparently a fan of Sev'ral Timez, as he is later seen cheering at their concert. He is also spotted riding through the crowd in the background at the end of the concert.
In "Land Before Swine," Old Man McGucket first appears at the abandoned church where he tags along with the gang to find Waddles in the abandoned mines and to get back his musical spoons that were stolen by the enraged Pterodactyl. After Soos breaks Dipper's lantern, everyone begins to fight but Old Man McGucket holds up a new lantern, saying that he fixed it, unaware of the adult pterodactyl behind him. Later, in the baby pterodactyl's nest, Dipper asks him if he has any inventions that could save them. He rummages through his hat for a while and then says "nope." Old Man McGucket then ends up getting eaten by a baby pterodactyl and pops out for a few seconds, but then gets gobbled up once again. Later, he is shown popping up from the hole in the church and saying "I just ate my way through a dinosaur!" while playing the spoons and laughing insanely.
In "Mabel's Guide to Fashion," Mabel, Candy, and Grenda give him a "flash makeover," which amounts to them drawing a smiley face on the back of his head, covering his actual face with his beard, and having him walk backward. He doesn't mind walking backward, claiming that it's the way his body naturally wants to move.
It is often theorized that McGucket owns a pair of shorts.
In "Sock Opera," he appears in a live action sock puppet form in a dream Mabel has during the credits.
In "Society of the Blind Eye," the twins, Wendy and Soos go to question him about being the author of the journals though he exclaims he doesn't recall anything before "1982." But after seeing a page in the journal with a strange symbol, he freaks out, expressing a memory of a group which the symbol belongs to who did something to his mind. He tells them the last thing he remembered involved the Gravity Falls Museum of History to which he accompanies the gang to afterward. After saving the gang from captivity, he regains his memory, revealing that he founded the Blind Eye Society, and created a device that will erase all memory of a certain thing. It also explained how he went crazy, as he used the device too much, and ended up erasing his memory wholesale.
In "Northwest Mansion Mystery," after the common-folk are allowed into the Northwests' party, Old Man McGucket is seen dancing on a table, but later pulls Dipper aside to inform him that he has fixed the laptop, and warns him of the incoming disaster that it predicts in about 21 hours. Dipper brushes it off and decides to have some fun for once, telling him that they will investigate later.
In "Not What He Seems," McGucket is seen sleeping next to the laptop as the first of the gravitational anomalies occur. Later, he is seen packing his things (including a raccoon wife), preparing to leave town before the Universe portal activates.
In "A Tale of Two Stans," young Fiddleford is seen in flashbacks working for the author and almost getting sucked into the portal.
In "The Stanchurian Candidate," McGucket is seen in the audience during the final debate of the mayoral election, indicating that he has not left Gravity Falls.
In "The Last Mabelcorn," McGucket is seen briefly during Dipper's glimpse into Ford's mind and during Ford's flashbacks, where he is noted as having glimpsed Bill's involvement with Ford and later become terrified by it.
In "Weirdmageddon 2: Escape From Reality," McGucket is revealed to have avoided capture or madness and has joined Stan's resistance group, which resides in the Mystery Shack.
In "Weirdmageddon 3: Take Back The Falls," McGucket leads a group of surviving creatures and characters to the Mystery Shack. He is one of the members of the rescue team that heads into Bill's domain and rescues Ford and the other townspeople. He is discovered to be the glasses on the Zodiac, due to him being scholarly, as explained by Ford. When Ford is rescued, he and McGucket reunite, and McGucket decides that he wants to forgive Ford. McGucket is seen at the end of the episode striking millions by sending his patents to the U.S. Government, and eventually buys Northwest Mansion. He also gets his memory back in the end.
Old Man McGucket is the "local kook" of Gravity Falls. He sports a long white beard with a band-aid and has shown the ability to use it as a limb. He has a large, pink nose with a few warts on it, blue eyes and a cast on his right arm. He wears an old brown hat that he got from a scarecrow, and brown overalls which are covered by his long beard. Around his feet, he wears white bandages. He is missing many teeth and has one gold tooth. He is also bald.
In his younger years, McGucket had similar features, however, his head was covered with long brown hair, and he did not have a beard. His nose was the same color as his face and was void of warts. He appears to stand more erect than his older self and wears glasses but not a hat.
In some Season 2 episodes, he wears gold glasses which have green lenses.
McGucket is the local kook, and is, as the title implies, mildly senile. However, it is shown that he is quite intelligent, and has the ability to create giant mechanical contraptions. This plays into his insanity, as he uses them for things like getting attention from his son, revenge against an old colleague for not coming to his retirement party, etc. He can seem to be a bit depressed at times, but this is only for brief moments. Instead, he's usually optimistic and occasionally even helpful. He usually enjoys dancing ridiculously and making up odd words and phrases. (e.g. scrapdoodle, smitheroons, donkey spittle, shim-sham, etc.). Some time after he regained his memories, McGucket's sane side has become a bigger part of his personality; his kookiness is more of a trait, which he sometimes uses to cover up his returning sanity. When he was younger, McGucket was highly religious and superstitious, being known to cross himself after walking over graves, and chastising Ford every time he says "What the devil!".
Dipper and Mabel Pines
Like the rest of the town, Dipper and Mabel think Old Man McGucket is crazy and are puzzled by his strange behavior; these major turn-offs contribute to the twins' lack of desire to interact with the old man. McGucket typically maintains a friendly attitude toward the kids, despite the fact that they do not return the action. McGucket occasionally gets involved in the kids' adventures, even playing a significant role at times. After Society of the Blind Eye, they are generally good friends.
Despite Old Man McGucket's love for his son and aspirations to spend time with him, Tate McGucket tends to avoid his father, for fear of embarrassment. Thus, the father becomes even more starved of attention and will go to ever greater lengths to catch his son's attention, but always unsuccessfully. After Weirdmageddon, the two seem to have mended their relationship, as shown in the end credits.
McGucket was previously married to Emma-May Dixon (Formerly Emma-May McGucket). But for reasons unknown, she left him. In response, he built a homicidal pterodactyltron. The incident was reported in the Gravity Falls Gossiper.
In "Not What He Seems", McGucket is seen filling a bag with items so he can "get out of town." One of those items is a raccoon. While forcing her into the bag, he says "Get in there, raccoon wife! Git!" She is his favorite raccoon.
Old Man McGucket has been shown to, on occasion, work for Gideon Gleeful; for example: manning the boat for Gideon and Mabel's "date" as well as building his Gideon-bot for him. Why he does these things and the full extent of their relationship is currently unknown. However, he does state that "I have a good feeling about that kid," suggesting that he is helping Gideon purely based on an inference.
During Ford's time in Gravity Falls, a younger McGucket helped with building the Universe Portal. After something went wrong with the project, McGucket quit, but his memories of the things he did and saw horrified him to the extent that he used his memory erasing gun in order to forget. He also founded the Blind Eye Society as a means to help other townsfolk forget bad memories. Ford discovered the Society and correctly suspected that McGucket was behind it, as seen in one of Journal 3's pages. Unfortunately, after continuous use of the gun on himself, McGucket started to lose his mind, forgetting words and eventually becoming the local town kook. Years later, during the events of Weirdmageddon, McGucket chose to forgive Ford for the events leading to their falling out, finally mending their friendship.
Soos, along with Wendy, Dipper and Mabel, helped McGucket restore his memory in Society of the Blind Eye. In Weirdmageddon 3, Soos is seen watching anime with him.
- 102. "The Legend of the Gobblewonker"
- 103. "Headhunters"
- 104. "The Hand That Rocks the Mabel"
- 106. "Dipper vs. Manliness"
- 107. "Double Dipper" (no lines)
- 108. "Irrational Treasure"
- 109. "The Time Traveler's Pig" (flashback)
- 110. "Fight Fighters"
- 111. "Little Dipper"
- 112. "Summerween"
- 114. "Bottomless Pit!"
- 115. "The Deep End"
- 116. "Carpet Diem"
- 117. "Boyz Crazy"
- 118. "Land Before Swine"
- 120. "Gideon Rises"
- 201. "Scary-oke" (no lines)
- 202. "Into the Bunker" (mentioned)
- 203. "The Golf War"
- 204. "Sock Opera" ( )
- 206. "Little Gift Shop of Horrors" (no lines)
- 207. "Society of the Blind Eye"
- 209. "The Love God" ( )
- 210. "Northwest Mansion Mystery"
- 211. "Not What He Seems"
- 212. "A Tale of Two Stans" (flashback)
- 214. "The Stanchurian Candidate" (no lines)
- 215. "The Last Mabelcorn" (flashback)
- 217. "Dipper and Mabel vs. the Future" (mentioned)
- 219. "Weirdmageddon 2: Escape From Reality" (no lines)
- 220. "Weirdmageddon 3: Take Back The Falls"
"I SEEN IT! I SEEN IT AGAIN!!!"
"Old Man McGucket, local kook. Are the wax figures alive? And follow up question: can I survive the wax man uprising?"
"You can run, but I'll still be in yer niiightmares!"
"Hit me with your best shot, Baldy. But my mind's been gone for thirty-odd years. You can't break what's already broken!"
"It's happening! The end times!"
"I've made some thingamadiculous robomajigs in my day, but this is the first one that won't be used for evil."
"I've tried forgettin'. Maybe I should try forgiving. Come here old friend."
- "Fiddleford" is the name of a manor in the United Kingdom. This foreshadows McGucket's fate of moving into a mansion.
- Old Man McGucket can play the banjo.
- Old Man McGucket was originally named "Crazy Larry." It was changed because Disney's Standards and Practices deemed the term "crazy" insensitive. 
- In an interview, Alex Hirsch joked about killing off Old Man McGucket in season 2.
- Old Man McGucket seems to have a recurring theme of eating strange things. By the end of Season 1, he appears to have eaten a baby pterodactyl, a book, and a novelty check. He also tried to eat Soos while he was in Waddles' body. When Soos explained that he was actually a human, McGucket replied: "That's what they all say!"
- He is currently married to a raccoon. This raccoon is obviously not the mother of his son.
- He has been referenced in multiple cryptograms.
- In the game PinesQuest, there is a cryptogram which when decoded reads "OLDMANMCGKNOWS."
- At the end of "The Golf War," there is one that deciphers to: "Old man sleeping on the green. Can't help but wonder what he's seen."
- In Society of the Blind Eye, a substitution cipher from the author read: "IF MY SUSPICIONS ARE CORRECT, THIS IS THE WORK OF FIDDLEFORD. DOES HE REALLY HAVE TO GO TO SUCH GREAT LENGTHS TO FORGET?"
- As revealed in Between the Pines, Old Man McGucket was originally going to sing a song about the Gobblewonker, and about how "it's gonna getcha", but it was cut because it made the episode's length too long and because they realized McGucket was a terrible singer.
- His middle name, Hadron, is a reference to a class of subatomic particles.
- McGucket was long suspected to be the author of the journals, and there was even a supposed leaked image of him Writing Journal 3. However, this turned out to be a prank created by Alex Hirsch.
- When the gang was watching the video of McGucket's memories of him descending into madness he references seeing the same creatures seen by Dipper and Mabel in season one, the first being "a colony of little men" which are the gnomes, the second creature "I saw something in the lake, something big!" which is similar to the Gobblewonker (and is likely the the living Gobblewonker seen at the end of "Legend of the Gobblewonker") and as a possible extension, he mentions stealing a hat from a scarecrow, which is the Summerween Trickster, and finally, he makes a triangle over his eye, which is Bill Cipher.
- During his time in the interdimensional portal, Fiddleford glimpsed at "the kind of places where Bill Cipher likes to hang out," which permanently damaged his mind.
- It is later revealed in Journal 3 that he saw Bill Cipher removing his exoskeleton to feed.
- McGucket seems to have Jargon Aphasia, a mental condition that causes a person to insert made up words into sentences without even realizing it, to the point where they're basically speaking an entirely made up language.
- In "Society of the Blind Eye" McGucket notices the bandage in his beard and wonders "Why does my beard have a bandage? Does that even make sense?" The bandage is from a minor traffic collision which happened on Day 189 of his memory erasing experiment. The bandage is visible in all memories that follow. Presumably, frequent use of the memory eraser caused him to overlook it.
- Old Man McGucket was originally conceived for the plot of "The Legend of the Gobblewonker." It was not until later in production that the writers thought to give him his backstory of working with Ford and inventing the memory gun. 
- After moving into Northwest Manor, Old Man McGucket renamed it "McGucket's Hootenanny Hutt!!".
- In "Lost Legends", it is revealed that his wife's name is Emma-May Dixon, formerly being Emma-May McGucket.
- Alex Hirsch stated on his Twitter that McGucket became the 45th president of the United States, and invented a vaccine for COVID-19 out of "gizmos." 
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