198k XP for killing the same mob over and over.

[Slush]

You have to be in Townlong Steppes.
Do quests leading up to Terror of the Dread Wastes - pick up this quest.
1. Kill Norvakess that is needed for quest completed.
2. Abandon the quest.
3. Run halfway up the hill and the quest giver will spawn again after a few seconds.
4. Pick up the quest again
5. go to 1.

The mob has 3,256,512 hp. On my Frost Dk, I use approx 50secs - 1min10 sec to kill it. Depending on the burrow.
The mob has a 1 minute respawn timer.
The mob gives you 198.000 XP if you are rested at lvl 89. Dont know how much on level 88. Apparently, Battle Standard of coordination bonus does apply.

If you are past this quest in you chain, I doubt it will work as its phased.