When I saw the new cutie marks of those three, I had something WWE-related in mind (The Shield, obviously), so I went and pulled this out of my head. And I think "Crusaders of the Lost Mark" has easily toppled "Slice of Life" as the best episode of FiM Season 5

My Little Pony: Friendship is Magic (c) Hasbro, Inc.
Art by MofetaFanBoy