I have been mulling over the concept of creative curses in world folklore, and the more I think about it, the more I realize how many there are. Even if one goes beyond the standards, like "eternal sleep" or "turning into various animals," humanity has come up with a stunning array of ways of messing with someone's life - an array that ranges from mildly annoying to truly miserable.
So, without further ado, here is my list of runner-ups:
Cast for all the wrong reasons, I always thought that Cassandra's curse is truly hellish: Constantly being right, and not being able to prove it to people around you, having to watch them run into their doom despite your warnings. Even as a kid I felt tremendously sorry for Cassandra, and marveled at the razor-sharp cruelty that Apollo displayed with this curse.
(Side note: Interesting to look at how Apollo attempts to "embrace" Cassandra, and when she rejects him, he curses her so that no one will ever believe what she says. There is a metaphor in there somewhere...)
Hilde, the Good Stepmother
In this Icelandic folktale, a mother's curse compels a princess to do three things: Burn down her father's palace, get pregnant out of wedlock, and kill a man. All three parts are fulfilled with minimal casualties, courtesy of the princess' kind and clever stepmother, Hilde. Part of the allure of the story is the curse itself (especially with the added weight of it coming from the mother), and part of it is the enjoyment of watching Hilde avoid disaster on all three counts, using technicalities.
Narts vs God
And while we are on technicalities: There is an Ossetian Nart saga where God curses the Nart heroes with food shortage. However much they work in a day on the fields, He declares, it will only ever amount to one bucket of wheat. The Narts' response is one for the ages: They start harvesting one handful of wheat a day - and it, per the word of God, still results in a full bucket. Boom.
I always found folktales where people "speak" things fascinating - in many versions of the tale of the Kind and the Unkind Girl, the good girl gains the power to speak/laugh golden coins, while the lazy girl ends up with something nasty. Most often, whenever she opens her mouth, frogs and snakes fall out. While in picture books this is usually portrayed as reptiles and amphibians manifesting out of thin air just outside her lips, somehow as a kid I always imagined her actually spitting them up. Either way, yuck.
I know I have been hung up on this folktale type ("The princess that turned into a man"), but here it is again: In many versions, it is a curse that changes the princess from female to male, and her male companions into female. The fun part is, it is intended as a curse, but the princess is usually quite happy with the result, and doesn't mind at all. Also fun is that the curse doesn't only take on people - it also affects their horses and other animal companions.
This one is actually quite common - a curse on a person, or a group of people, to wander aimlessly without being able to stop or settle down. The most famous examples include the Flying Dutchman, the Wandering Jew, and the Roma people (I found this one quite recently in a collection of Romani folktales). It is usually punishment for lack of hospitality given to someone, lack of compassion shown, or for a challenge against God - and as a side effect, it sometimes comes with eternal life, so that the person doesn't only wander across space, but also time... I always found the thought of such a curse epic in magnitude, and heavily charged with emotions.
There are, of course, many more curses in legend and lore. These are simply the ones I have given the most thought as a storyteller, ideas that made me think, shudder, or wonder.
What are some spells in lore that you would NOT want to be under?...