Trixie, or Trixie Lulamoon, is a female unicorn pony and traveling magician. She is the main antagonist of Boast Busters and Magic Duel and a supporting antagonist in the chapter Twilight Sparkle and the Crystal Heart Spell. She also makes major appearances in No Second Prances and various comics. She makes minor appearances in Bridle Gossip, The Return of Harmony Part 1, The Cutie re-Mark - Part2, other IDW comics, and other chapter books. She tends to speak in the third person and refer to herself as "The Great and Powerful Trixie". The name Trixie is often a diminutive form of Patricia or Beatrice/Beatrix.

Trixie serves as a secondary antagonist in Rainbow Rocks. She first appears with her bandmates in the gym painting a sign for the CHS Musical Showcase. She is among the students who sneer at Sunset Shimmer when Principal Celestia brings up the Fall Formal. During Better Than Ever, she photobombs Photo Finish's photo of Big McIntosh. She also appears in the cafeteria during the Dazzlings' song.

In the Battle of the Bands, Trixie and her bandmates participate under the name "Trixie and the Illusions" and perform the song Tricks Up My Sleeve. They eliminate Lyra Heartstrings and Sweetie Drops in the second round of the competition. Trixie and the Illusions are the last opponents for the Rainbooms before facing the Dazzlings in the finals.

When the Dazzlings manipulate Principal Celestia and Vice Principal Luna into advancing the Rainbooms to the finals, Trixie feels she's been cheated, which the Dazzlings use to their advantage by encouraging Trixie to get rid of the Rainbooms. Trixie ambushes them during their rehearsal and drops them through the stage's trap door to the basement underneath. With the Rainbooms having apparently forfeited, Trixie and her band are able to play in their place.

Even after the Dazzlings are defeated and their spell is broken, Trixie still declares herself the greatest musician at Canterlot High and attempts to escape via smoke bomb. She is last seen trying to climb over the back of the bleachers as part of her escape, only to lose her balance and fall off.

A brief running gag in the film involves Pinkie Pie always catching Trixie hiding each time she "disappears."