Video here: https://www.youtube.com/watch?v=zc8fa59W5pk
I wanted a proof-of-concept that my kitchenaid attachment profile works, so I remixed nagylevin's unicorn horn to make it smaller and rotate! Tested on a Kitchenaid Professional 5 Plus, but it should work on most or all kitchenaids.
EDIT 1/13/2019: retooled the large attachment to reduce delamination at the base of the horn. Should work better now!
model needs to be printed with support. Once it's done, you should be able to snap off the support at the base and carefully dig out the support that separates the unicorn horn from the sleeve. after that it should rotate freely, but if you have a bit of stringing it might take a little effort.