To kill a Unicorn is to bring bad luck and the hatred of nature itself down upon the foolish. It is said that the mate of a unicorn that is murdered will turn horrible in it’s pain and anger, turning against nature to hunt and kill the murderer of it’s mate. It turns dark and soulless and seeks nothing but the death of it’s enemy.
For a creation of the Black Tide of Acqua,death never truly befalls it. As long as the most vital part of it survives,the foul thing will continue to exist. In a certain sense..
A PC Conjurer or summoner, basically any mage whose sole purpose in life is summoning creatures to aid in battles and various situations, is cursed with a hex, and needs to find a way to undo the curse...before he goes mad, or his fellow PCs throw him out of the party, or worse.
Everything he/she summons, never goes away. So you'll have to figure out what the heck to do with that dire bear or fire elemental once it's done fighting the orcs for you. Eventually a caravan of bizarre creatures either annoyingly ends up following the summoner around, or they go off to cause mayhem elsewhere. Bad news for the poor spell-caster regardless.