PROCEED WITH CAUTION
Rainbow Factory is a Grimdark Fanfiction inspired by the song of the same name (www.youtube.com/watch?v=YRx_iXgLAyw). The story involves the Cutie Mark Crusader, Scootaloo. She fails a flight exam and is sent to the place where all the pegasi who fail go along with 2 companions.
They get to the place where rainbows are made, and discover the dark secret that lies inside. As her friends are picked off one by one, lead to an atrocious death, Scootaloo and Aurora bust down a door, but this leaves Aurora is far too tired to go on.
Scootaloo runs off, only to end up back where she started, this time with Rainbow Dash. Scootaloo's fate is left uncertain at the end of the story.
The fic can be found here: https://docs.google.com/document/d/1td5r9BGGA7l2-rnlFTnVrJN2NdZclcVWUMoCqaSujnM/edit?hl=en_GB
If you would like some mind bleach after reading, watch this video. Be warned, it will ruin the fic forever.