The Muddy Hand is the main antagonist of the novel Diary Of A Wimpy Kid: Dog Days and a minor antagonist in its 2012 film adaptation. Appearing as the villain in the fictional the horror movie "Hello: You're Dead" and acting as a subject for Greg's paranoia throughout the whole book, in the movie it is a campfire story passed down through generations of Wilderness Explorers and a favourite of Fregley's
In the book, the hand appeared as the main villain in the horror movie Greg and Rowley were watching. According to Greg the movie was very cheesy and campy however he became terrified at the end when the film's twist appeared (being that whoever sees the hand next would be its newest victim and the Hand turned to the camera at the end of the movie). Greg appears paranoid about the hand catching him throughout the remainder of the novel. When Greg and Rowley camp outside a game store, Greg gets chocolate all over his hand and pulls a prank on Rowley, who smashes Greg's hand with a hammer. However, after Dog Days, the hand is never mentioned again meaning Greg probably got over it.
In the movie, the hand had even less of a role and only appeared as a campfire tale told by Fregley during the Wilderness Explorer camp. The story involved a group of wilderness explorers who were assisted by a good hearted old woodsman who accidentally chopped off his own hand. The explorers were terrified and fled leaving the woodsman to bleed out and die, they later returned to try and help but only found his disembodied hand. The boys disappeared that night with a muddy hand print being the only hint as to their fate. Greg while being afraid of the story didn't believe it however when he saw his camp manager pretending to be the hand he jumped and screamed in fear and later after seeing his dad Frank's muddy hand emerging into the tent he whacked him with a mallet in fear and defence. The hand has never been mentioned again since.
- In the movie version of Rodrick Rules, Greg and Rowley watch a horror movie called "The Foot" which is an obvious reference to the muddy hand.