A group called Mane6 has apparently been working on a Little Pony fighting game, My Little Pony: Fighting is Magic, based off of the My Little Pony: Friendship is Magic TV show. The fighting game was completely non-profit and has been in development for at least two years.
A legal representative from Hasbro sent the developers a cease and desist letter. The C&D letter asked the developers to cease developing the game, remove any material that might contain My Little Pony characters, names, locations or related elements from the sites Mane6 control (Their site, YouTube, twitch), and “cease any further use of [their] MY LITTLE PONY property”. You can read the blog post by clicking this link.
Fans of the scrapped game has offered their support, and has even started a petition. About 10k has signed the petition of 100k needed.