Flying Princess Lilacia Pony Head, or just simply Pony Head, is a princess from the Uni dimension and one of Star's best friends. She currently attends St. Olga's Reform School for Wayward Princesses because of her rambunctious behavior. She serves as a supporting protagonist
She is voiced by Jenny Slate in the English version of the cartoon, and by Monica Bertolotti in the Italian version of the cartoon.
Pony Head is literally the head and neck of a unicorn without a body. She has light blue fur, a pink mane (which constantly flows and flutters), teal eyes with gold stars for pupils, and a teal, striped horn. On each side of her neck, there is a pink heart. Sparkles and glitter tend to fall out of the bottom of her neck.
Pony Head can be quite bold and rash, as well as sarcastic and laid-back. She can be competitive, as seen when she is playing video games with Marco. Though she can be rude and underhanded, she is loyal to her friends and willing to endanger herself to help them. She is also quite possessive, initially trying to get rid of Marco so she could have Star all to herself.
- Star Butterfly: Pony Head has been best friends with Star since they were kids and loves it when they get to have fun together. However, she is very possessive of their friendship and is upset by Star also calling Marco her best friend. Star's disappointment in Pony Head lying to her about ditching Marco leads Pony Head to give her pair of dimensional scissors to Star and bravely sacrifice herself, getting caught by the guards to save Marco.
- Marco Diaz: When finding out that Marco is Star's other best friend, Pony Head gets jealous and threatens him to not get between her and Star. She calls him "earth turd", tries to push him off the dance cloud in the Bounce Lounge, and ditches him at the Amethyst Arcade. However, once she realizes how important he is to Star, she goes back to save him from the guards. Her heroism puts her on good terms with Marco, and when she departs for St. O's, she appreciates him telling her good luck and calls him by his real name. Though she still insists on being known as Star's "best bestie", she remains on good terms with Marco when next they meet. In "Goblin Dogs", Pony Head tries to monopolize Star's attentions, making Marco interact with her friend Kelly. But she still treats Marco quite well, even addressing him by name throughout the adventure (except in one instance).
Pony Head can use her horn to shoot laser beams or function like a drill. She can also levitate or fly at high speeds. In "Sleepover", it is shown that she is strong enough to carry several people at once (though with great difficulty). In "Pizza Thing", she uses her horn to magically restore a crushed car, then has it drive itself back to its owner.
- Pony Head is based off previous artwork by Daron Nefcy.
- According to her signature on a document in the episode "Death Peck,' her first name is Lilacia, so Pony Head is her lastname.
- In early concepts, Daron Nefcy wanted Pony Head's design to look like she was "drooling, and blood dripping out of the neck but then really sparkly and really big eyes".
- She can wreck an entire dimension consisting of video game consoles using only her ability to shoot laser beams out of her horn.
- "Goblin Dogs" reveals that she can store things inside her neck.
- In "Sleepover", Pony Head reveals that she doesn't have a stomach. She also admits to having a crush on herself.
- Pony Head is the eldest of 14 daughters.
- Pony Head is the similar of Amethyst from Steven Universe.
- Both are wild.
- Her English voice actress, Jenny Slate, also voiced Huntress Wizard in Adventure Time, Gidget in The Secret Life of Pets and Dawn Bellwether in Zootopia