She is voiced by Devyn Dalton while Shannon Chan-Kent, who also does Pinkie Pie's singing voice, Smolder and Silver Spoon, provides her singing voice.
Ocellus was first previewed in a 2018 "MY LITTLE PONY SERIES" image within Hasbro 2017 Investor Day webcast presentations from August 3, 2017.
In zoology, "ocellus" is a term for a simple eye or eyespot, such as on invertebrates, or an eye-like marking such as on a peacock's feathers.
In the season eight premiere School Daze - Part 1 and Part 2, Ocellus enrolls in Twilight Sparkle's School of Friendship as a student, having been brought to Ponyville by Thorax to represent the changelings. In her debut, she behaves shyly, avoids talking to others, and frequently keeps her real form hidden, only dropping her disguises at Thorax's insistence. When Twilight's strict adherence to the Equestria Education Assocation's guidelines causes the school courses to be dull and boring, Ocellus cuts class with Sandbar, Gallus, Smolder, Yona, and Silverstream, becoming good friends with them in the process. When they return to school for Friends and Family Day, they accidentally ruin the event and cause damage to the school. Chancellor Neighsay of the EEA perceives their fun and games as an attack orchestrated by other non-pony creatures, and the offended tribe leaders pull their students out of school, including Ocellus.
Not wanting to say goodbye to each other after the school is closed, Ocellus and her friends go into hiding at the Castle of the Two Sisters. The six have fun together at first, but they eventually come under attack by ferocious puckwudgies, and the Mane Six come to their rescue. When Ocellus and her friends are asked to come back to school, they are reluctant to continue their boring lessons, but Twilight and the others assure them things will be better and more fun than before. After Twilight defies the authority of Chancellor Neighsay and reopens the School of Friendship, Thorax allows Ocellus to re-enroll and expresses faith that she will make the changelings proud.
In Horse Play, Ocellus takes part in Twilight's play about Princess Celestia.
In The Parent Map, Ocellus appears outside the Castle of Friendship.
In Non-Compete Clause, Ocellus and her classmates are taken on a teamwork field trip by Applejack and Rainbow Dash. The trip doesn't go very well, chiefly due to their teachers' arguing and competing with each other. When a canoe trip results in the group falling into the water, Ocellus (taking on the form of a seapony) saves Yona alongside Silverstream. The group then takes a nature walk, which ends with Applejack and Rainbow Dash trapped over a ravine filled with bite-acudas. The students work together to save their teachers, Ocellus taking on the form of a larger bite-acuda in order to scare the others away. Once they return to the school, Ocellus and her classmates tell Twilight that Applejack and Rainbow Dash's arguing taught them how not to work together, and nominate them both for the next teacher of the month award.
In Marks for Effort, Ocellus takes part in Pinkie Pie's lesson of sharing cupcakes and compliments. After Pinkie demonstrates to Ocellus what to do, she gives Yona a cupcake, and compliments her on her strength. She is later seen exiting the school with her friends after a test.
In A Matter of Principals, Ocellus and her classmates are shown various magical artifacts by Twilight just before she is summoned by the Cutie Map. During the Spell-venger Hunt, Ocellus is paired up with Smolder, and they find the Helm of Yksler, but they get chased by a suit of armor animated by Discord. She and her friends are present when Starlight Glimmer apologizes to Discord for not including him, and offers him the job of "vice headmare".
In The Hearth's Warming Club, after a prank ruins the Hearth's Warming tree, Ocellus and her friends are all suspected for it and charged with cleaning up the mess. During the cleanup effort, she tells her friends how much she loves Hearth's Warming and describes the Changeling Kingdom's first celebration of the holiday. When Gallus confesses that he was the culprit and is punished with extra friendship lessons over the holidays, Ocellus and the others all choose to stay with him.
In Friendship University, when Ocellus and her classmates hear about Flim and Flam's Friendship University, she points out that it teaches the same lessons in half the time, believing that will provide twice the learning.
In The End in Friend, Ocellus and her classmates observe Rainbow Dash and Rarity as part of Twilight's lesson on compromising in friendship.
In A Rockhoof and a Hard Place, Ocellus is one of the students in Rockhoof's class and the one who first mentions the stone sleep spell to him.
In What Lies Beneath, Ocellus and her friends start to question their friendship due to comments made by Cozy Glow. They then discover a cavern beneath the school, where the Tree of Harmony interacts with them. As part of a test, the Tree forces Ocellus to confront her fear of the changelings' dark past, causing her to assume the form of Queen Chrysalis. She overcomes her fear with the help of Smolder, and they escape with the rest of their friends.
In the season eight finale School Raze, Ocellus and her friends go on a field trip to Cloudsdale just before a crisis in Equestria causes magic to start disappearing. After Twilight and her friends leave for Tartarus to investigate, Ocellus and her friends discover Chancellor Neighsay taking over the school in their absence, and Neighsay captures them under suspicion of stealing Equestria's magic themselves. After Sandbar and the Cutie Mark Crusaders help them escape and reveal Cozy Glow's true sinister nature, they try to free a magically-trapped Starlight Glimmer, but Cozy catches them and convinces the students to turn on them. Ocellus and the others get trapped with Starlight and are nearly sucked into another realm with all of Equestria's magic, but they are saved by the Tree of Harmony, and they succeed in foiling Cozy Glow's plans.
Best Gift Ever
In the holiday special My Little Pony Best Gift Ever, Ocellus and the rest of the Young Six appear at the beginning boarding the Friendship Express. Ocellus also makes a brief cameo during The True Gift of Gifting celebrating Hearth's Warming with Pharynx, Thorax, and several other changelings at the Changeling Kingdom.
Among the Young Six, Ocellus is portrayed as very shy, similarly to Fluttershy. As a way to avoid socializing with others and blend into the background, she commonly transforms into creatures around her. Ocellus is also the most academically inclined among her friends, being the only one to remember Twilight and Fluttershy's lessons. In What Lies Beneath, Her deeper fear is worrying that she will be like Queen Chrysalis being evil and cruel.
Ocellus appears on the cover of the adaptation Meet the New Class.
Ocellus appears in the promotional music video Saved by My Friends.
- Ocellus was never seen in the episode To Change a Changeling. Therefore, she did not help during the battle against the Maulwurf, although she may have interacted with it before the episode.
- Ocellus is the only member of the Young Six to have a different voice actor when singing.