The smile killer

Rainbow was horrified. Who could have done this?

" I-I don' unders'and! " Cried Applejack.

" There's gotta be a reason for this! " Twilight shouted in protest.

Fluttershy just cried.  So did Rarity.

Pinkie Pie came bouncing round the corner. She stopped at the body.

" Oh my! How could somepony do such a thing? " She said.

" I don't know, Pinkie.. " Rainbow said.

They noticed a tape by the body. They played it, but it was impossible to see or hear.

" Damnit, that was a clue! " Twilight said.

Rainbow dash pulled on a tape string and heard something.

"now you can smile forever! "