Heh. Ive seen my share of this as well. I've had several evil-to-the-core baddies reduced to a cat-call by my PCs. Father Yoakum turned into Father Stroke-um. Err, Count Piscalu is now count pissed-at-you, etc. etc. It hasnt happened in a long time, but I never really got to upset about it since the PCs played it up in-character and used it as part of the game. Also, Count Pissed-at-you got EXTREMELY pissed at them for making this little name up, and caused quite a tremor throughout the local countryside as his minions went on a witch hunt for the snivelling weasels that dared to denigrate his title and station.