The pig changing scene
I'll be the first to admit, that this particular scene always scared and disturbed the crap out of me:
https://www.youtube.com/watch?v=t6xYJbVT7BE
https://www.youtube.com/watch?v=SGPtl_MmXUQ
https://www.youtube.com/watch?v=eBNY1zgt6q4
I was kind of expecting others to bring it up sooner or later:
http://www.sciencebuzz.org/blog/most-frightening-scene-willow-become-reality
https://macmcentire.com/2019/01/21/willow-1988-rewatch-part-40/
https://www.thebooksmugglers.com/2015/06/old-school-wednesdays-may-watchalong-summer-movie-series-willow.html
https://metro.co.uk/2015/02/06/13-kids-movies-from-the-80s-that-were-seriously-dark-and-scary-5051659/