Peg

Peg is Bloom's pet horse that she receives from her parents as a gift in "Magical Adventure".

Appearance
She is a white horse with brown eyes and long yellow mane and dark brown hooves. She wears purple muzzle and headcollar, and red saddle and neckband with golden trims.

Once she transformed, she earns creamy bird-like wings with patterns that have yellow edges and a horn.

Season 6
In "Acheron," she transports Daphne to Domino's courtyard for her wedding. In "Winx Forever," she transports Daphne and Thoren away from Domino after they are wed.

Magical Adventure
After Bloom meets Sky in Domino, Sky teaches Bloom how to ride Peg.

Peg helped Bloom during the battle in the ship. And at the end of the movie, she transforms into a Winged Unicorn by eating the seedling on Havram.

Magical Abilities
Peg is a skilled horse and is able to run fast. After becoming a winged unicorn she is able to fly with her wings. It is possible she may be able to control the transformation, as it disappears when the magic pollen is gone and then reappears after magic is restored, just like with the Winx's Believix.

Trivia

 * Peg in his transformed form is a Pegacorn, a winged unicorn found in many legends.
 * Peg and his name were inspired by Pegasus, a divine winged horse from Greek Mythology. Alternatively, Peg's name is just a shortened form of "Pegacorn", which it itself a portmanteau of "Pegasus" and "Unicorn"
 * Later in Season 7, Bloom bonds with Elas the Unicorn, who becomes Bloom's second horse-like animal pet.
 * Peg also appears in Winx Club: Magical Adventure an online game on Nickelodeon's website.
 * Peg does not have a horn in the series.
 * This may be an animation error.