Noun: Bitch-Pigeon > Someone that comes out of nowhere and shits all over your life. Metaphorically.

I got this one from @TheBloggess, as an answer to her request:

"I need the most ridiculous insult ever. Cock-knocker. Douche-canoe. Something like that. It's for Satan, if that makes it better."

@thisisroxanne kindly replied:

"@TheBloggess Bitch-pigeon. Its someone that comes out of nowhere and shits all over your life. Metaphorically."

Hmmmm.....
Somehow it has been on my mind ever since...