Hello!
Well, I did some research, but couldn't find anything like this.
So, yea - I was doing the daily quest in Ogri'la where you got to strangle the nether rays and hand them in to the quest giver (duh....) I don't remember the name of the quest, but if you are doing the dailys in Ogri'La, I'm sure you know what I am talking about.
Anyhow; I was trying to get a pug to karazhan to get some more badges aswell as offspecc gear. So.. I found a group, and joined then. at start it was a normal group, and I could continue with my quest, but afterwards, when the group leader changed it to raid group, I didn't receive the "capture nether ray" accomplimishments for the quest.. So I could capture as many as I would like to.
Be aware: It will cause extremly low fps!! =P
EDIT: I am not quite sure if you can capture as many as you want even though you've completed the quest. I am going to test this when the dailys reset. Anyhow, if it don't; Enjoy low fps! =P
Regards
~Xps