My witch Beatrix Beeswax got the Curse of the Night Specter (or something similar, don't recall the exact name), which was pretty awful. It states "You're being hunted by a Night Specter, so you can't sleep." So essentially Freddy Kreuger. Her energy tanked, and even if I used a Potion of Plentiful Needs to counteract it, it dumped again the following hour. She was unable to sleep or nap (but also unable to pass out), so she was just miserably low on energy until I was able to expunge the curse. That took a while because she didn't know Decursify yet and didn't have a Curse Cleansing potion, so she had to deal with it for several days.
Then it got worse.
The Night Specter ACTUALLY SHOWED UP. He was a Noferatu looking thing in a tattered robe, ghostly and sparking electricity. He followed Beatrix around for many hours screeching at her and causing her to stop whatever she was doing to flee in terror. He eventually disappated, but the curse remained. Safe to say, I got rid of it immediately, cause that thing spooked the daylights out of me.