In Lawnmower Dog, what parody dream character helps Rick and Morty?

In “Lawnmower Dog,” the parody dream character who helps Rick and Morty is Scary Terry. He is a legally safe knockoff of Freddy Krueger, complete with a bladed glove, menacing dream-stalking, and a deliberately exaggerated horror-movie persona.

Rick and Morty encounter Scary Terry while escaping through the dreams of Morty’s math teacher, Mr. Goldenfold. After entering several layers of dreams, they find themselves pursued by Terry, who can follow them from one dream environment to another. The chase echoes both Inception’s nested dreams and A Nightmare on Elm Street’s dream-killer mythology.

Rather than simply defeating Terry, Rick and Morty discover that he is anxious about failing at school and disappointing his family. They enter his dream and help him overcome that humiliation. Terry then returns the favor by guiding them back toward reality. The episode aired December 9, 2013, and its title also references the 1992 film The Lawnmower Man.