The quest "Holed-up" from Sya Zhong (Kun Lai summit, 43, 88.2) in Pandaria is a quest where you escort four pandas to safety. If you begin the quest while in a raid group, for example by porting out of LFR without leaving the group, you will find the quest dialogue for each NPC can be repeated indefinitely creating potentially infinite numbers of NPC's.
There is no point to this exploit other than creating truly vast numbers of pandas.
This is how it looks: Lots Of Pandas.
