Old Man McGucket

Old Man McGucket is the oldest known person in Gravity Falls and is the local kook. He appears in "The Legend of the Gobblewonker," "Headhunters," and "The Hand That Rocks the Mabel."

The Legend of the Gobblewonker
In this episode, McGucket is seen running up to everyone and telling them that he actually saw The Gobblewonker and that it wrecked his boat but he is made fun of by the crowd and the police.

Later it turns out that he built a mechanical version of The Gobblewonker to gain attention because his son never wants to spend time with him any more. He also tells the twins that he also made a homicidal pterodactyl when his wife left him and an 80 ton shame bot when his friend Ernie didn't come to his retirement party. Then he continued on working on his Death Ray.

Headhunters
McGucket was present at the re-opening of the Gravity Falls Wax Museum. He also asked if the wax statues were alive and if he could survive the wax man uprising to which Mabel answered yes.

Dipper and Mabel later find him at the junkyard near a dog house. They wave at him to see if he uses his right or left and he waves with his right hand which has a caiman on it.

The Hand That Rocks the Mabel
McGucket rows the gondola that Mabel and 'Lil Gideon use on their date. Also he was singing while he was rowing