Twilight Sparkle has a new spell that can make equipment work more efficiently and faster than before. She decides, since rainbows are so rare, to try and help the pegasus ponies on making more of them. Rainbow Dash takes her to the place but then a dark secret is brought forth.

it was a dare because i went on about how much better Rainbow Factory could have been so i rewrote it in my own way so here it is.

Warning: Death/Gore/Experiments

I'm sure you can understand where this is going.