Monsters In Discuise

You thought the invasion ended when Cadence and Shining Armor blasted away the changelings with their love, didn't you? Its not. The truth is, few ponies still exist. Derpy Hooves was first for the comeback, you could even see that. Different voice, different eyes. Then Bonbon, different voice every time, a very forgetful changeling. From there, they kept getting replaced. They just kept the ponies with the most love alive, like Cadence and the most of the mane 6. They had to get rid of Fluttershy and Shining Armor, though. Fluttershy kept turning into a bat and attacking changelings, and if she stayed it would complete the elements of harmony which could lead dangerous. They got rid of Shining Armor since they didn't want Cadence and Shining Armor to blast them away again.