One day outside Ponyville, a huge bouncy castle appeared. Nopony knows why, but it didn't seem to be causing any harm at all.
That is, until the Cutie Mark Crusaders end up getting lost in its bouncy halls. So it falls to Pinkie Pie to venture into the rubbery lair and save the day!
Lyra also tags along for some reason. She's not the hero type.
(A 400 follower special my followers wanted me to do, and I'm stupid enough to do it.)