The Muddy Hand

The Muddy Hand is a disembodied hand made of mud that appears in one of Rodrick's horror movies entitled "Hello, You're Dead". In it, the Muddy Hand travels the countryside looking for victims to strangle, and the last person who sees it is always the next victim. The film in question freaked Rowley out, and Greg at the end (where the Muddy Hand strangles its last victim and walks straight at the screen, implying that the viewer was its next victim). This made Greg and Rowley paranoid that the Muddy Hand was out to get them (despite being a fictional character). It was only mentioned in "Dog Days".

The Muddy Hand