Derpy McDerperson (Or more commingly knowing as Derpy) is the secondary character in Hoopla!!!
The character is called "Derpy" on-screen in The Last Roundup, detailed below. The episode's writer noted that the character's name in the script was originally Ditzy Doo, and she was requested to change the name to Derpy as a "tip of the hat" to the fans. Lauren Faust notes in her Bronies Documentary interview that she imagined Derpy as a "Harpo Marx kind of character who didn't speak and who no one really called out by name", leaving her mysterious and "a blank slate for the fans." In the script for No Second Prances, she was referred to as "Derpy".