The flash version of the infamous "Cupcakes" fanfic. I loved this story, so I wanted to create an equally disturbing flash video about it.
In case you didn't know what this is about, here is a summary: Pinkie Pie invites Rainbow Dash to Sugarcube Corner so that she can help Pinkie make cupcakes. Pinkie then drugs Rainbow and tortures her, which involves a lot of disembowelment. She did so with the intention to make Rainbow Dash into a cupcake.
You could find the story by just googling "cupcakes fanfic."