In Street Magic, the tone is very gritty - supernatural dregs of humanity sort of stuff. Its threats are accordingly um, colorful. Yeah, colorful... Most of them start out with the threatener's foot going up the unfortunate victim's ass, but what happens from there is where the entertainment kicks in (no pun intended). I was laughing out loud at some of the threats, and coming up with so many unique ones had to be a challenge. When I start the second book in that series, I've decided to make a list of all the curses, just as a writing awareness exercise.
Irena in Meljean Brook's Demon Forged is a bit barbaric, so her curses and insults focused heavily on animal-involved romantic exploits. Now, I'm not in favor of animal smexxing, but calling someone a 'serpent-f*cking whatever' brings up funny mental images. Irena was also an equal opportunity blasphemer - no animal was subjected to the same humiliation twice, so by the end it was entertaining just to see what animal would be picked on next.
Can't come up with any good obscenities? Not a problem. Online random generator site, Serendipity, has a Cuss-o-matic to help you out. Some of the curses it generates are pretty silly, but it's a good way to get started. I'm particularly fond of "Flaming mother of a pestilent kangaroo-abusing scorpion!" Ah, good times.
Have you guys heard or read any good curses or threats recently?