My Little Pony Equestria Girls: Forgotten Friendship

My Little Pony Equestria Girls: Forgotten Friendship is an upcoming hour-long Equestria Girls special.

Production
A pony, appearing both in this special and in Friendship Always Wins, was previewed in a 2018 "MY LITTLE PONY SERIES" image within Hasbro 2017 Investor Day webcast presentations from August 3, 2017.

A novelization of the special, titled A Friendship to Remember, was published on December 5, 2017.

From Discovery Family
"In this brand new one-hour special, Sunset Shimmer is shocked when she discovers she’s been erased from her friends’ memories, leading her to search for the magic and the perpetrator who did such a dreadful deed."