In an infinitely improbable set of events, Twilight Sparkle, Sunny Starscout, and other ponies of all generations meet at the Restaurant at the end of the Universe, make friends, and get thoroughly confused about the nature of the multiverse.

A quantum superposition of all pony generations with the Hitch Hikers Guide to the Galaxy. If you are not familiar with that, this will not make much sense.

If you are familiar with it, don’t expect it to make much more sense.