Pegacorn

It was a flying horse — no, a unicorn — or a pegacorn? — feathery wings outstretched.

Pegacorns have grown in both popularity and population since their worldwide introduction during the 1980s. While they had existed for eons prior, few unicorn farmers wished to voluntarily care for both the temperamental nature of the Pegasus and the attention-craving disposition of the unicorn. However, when those farmers had the opportunity to soar high and fast into the clouds on the Pegacorn, they had an abrupt change of opinion.

At the end of each episode of My Little Pony: Friendship is Magic, one of the show's cartoon ponies dictates a letter to the pegacorn Princess Celestia, telling her what she's learned about friendship.