Yes, Season 5, Episode 11 "The Copycats" of The Amazing World of Gumball is a parody.
The episode is a parody of the popular manga and anime series "Death Note," and features a character named Sarah who discovers a notebook that allows her to control people's actions by writing their names in it. This is a direct reference to the premise of "Death Note," in which the main character, Light Yagami, discovers a similar notebook and uses it to try to rid the world of criminals.
In "The Copycats," the characters from The Amazing World of Gumball take on the roles of the characters from Death Note, with Gumball and Darwin playing the roles of Light and L, respectively. The episode also includes several visual and auditory references to Death Note, such as the use of dramatic music and the appearance of a Shinigami, a supernatural creature from the show.
Overall, the episode uses humor and satire to poke fun at the serious tone and dramatic themes of Death Note, making it a clear parody of the series.