Answer based on context:

When comparing A Nightmare on Elm Street with the other top-grossing horror series—Childs Play (film series), Friday the 13th (franchise), Halloween (franchise), the Hannibal Lecter series, Psycho (film series), Saw (franchise), Scream (film series), and The Texas Chainsaw Massacre (franchise)—and adjusting for the 2010 inflation, A Nightmare on Elm Street is the second highest grossing horror series, in the United States, at approximately $583.4 million. The series is topped by Friday the 13th at $671.5 million. Closely following A Nightmare on Elm Street is the Hannibal Lecter series with $579.4 million, then Halloween with $547.8 million, Saw with $404.5 million, Scream with $398.3 million, Psycho with $370.3 million, The Texas Chainsaw Massacre with $314.6 million, and the Childs Play film series rounding out the list with approximately $199.7 million.

Which films series are the top two grossing series?
A Nightmare on Elm Street