Principal Abacus Cinch is the main antagonist of My Little Pony Equestria Girls: Friendship Games. She is a headmistress of Crystal Prep Academy. She demonstrates great pride in her school and its reputation as the undefeated winners of the Friendship Games every four years—so much pride, in fact, that she views rival institute Canterlot High School's recent boost in athletics and academics as a threat. In order to maintain Crystal Prep's reputation, Cinch forces her brightest student Twilight Sparkle to compete in the Games, going as far as to threaten revoking Twilight's application for an independent study program to ensure she competes.
During her visit to Canterlot High School, Cinch displays considerable disdain toward the school and its choice of Games competitors, comparing their selection process to a "popularity contest." She interrupts the welcome party that the school holds for their rivals to assure everyone that Crystal Prep will win the Games like it always has.
During the Tri-Cross Relay event of the Games, Cinch witnesses Twilight's amulet open a dimensional rift and release a carnivorous plant, and she watches Rainbow Dash pony up. She accuses Principal Celestia of cheating, and when Celestia suggests ending the Games in a tie, Cinch refuses, determined to prove that Crystal Prep can win regardless of the presence of magic.
In the final round of the Games, Cinch and the Shadowbolts pressure Twilight into releasing the magic from her amulet and using it against the Wondercolts, justifying it as fighting fire with fire. Her hubris results in the creation of Twilight's evil alter ego Midnight Sparkle. As Midnight slowly destroys the world around her, Cinch retreats into hiding.
After Twilight is returned to normal, Cinch demands that Principal Celestia forfeit the Friendship Games, citing Canterlot High's unfair advantage of using magic. However, the Shadowbolts turn on their principal and blame her for Twilight's wicked transformation. Cinch says that she plans to report the incident to the school board, but Celestia, Vice Principal Luna, and Dean Cadance inform her that no one would believe her story. In an effort to save face, she leaves the school with calm dignity.
Throughout the film, Cinch's scenes are often musically accompanied by a rather sinister-sounding tango.
- Principal Cinch will become the enemy of Pooh, Ash and Thomas in Pooh's Adventures of My Little Pony: Equestria Girls - Friendship Games.
- Principal Cinch will become the enemy of Tino, Littlefoot, Doraemon and their friends in Weekenders Adventures of My Little Pony: Equestria Girls - Friendship Games.
- Principal Cinch will become the enemy of Crash Bandicoot, Ryan and thier friends in Ryan's and Crash's Adventures of My Little Pony: Equestria Girls - Friendship Games'.
- Principal Cinch will become the enemy of Lilo in Lilo & Stitch's Adventures of My Little Pony: Equestria Girls - Friendship Games, after joining with Lord Zedd and his army.
- Principal Cinch will also team up with Ivan Ooze in Season 2 of Power Rangers Harmony Force.
- She will make her appearance in Team Robot In Pokemon Movie: Volcanion and the Mechanical Marvel.